Fraksiya - Fraction

To'rtdan biri (to'rtdan biri) olib tashlangan pirojnoe. Qolgan uch to'rtdan biri ko'rsatilgan. Nuqta chiziqlar tortni teng qismlarga bo'lish uchun qayerda kesilishi mumkinligini ko'rsatadi. Kekning har to'rtinchi qismi kasr bilan belgilanadi 1/4.

A kasr (dan.) Lotin fraktus, "singan") butunning bir qismini yoki umuman olganda har qanday teng qismni anglatadi. Kundalik ingliz tilida gaplashganda, kasr ma'lum o'lchamdagi qancha qismni tasvirlaydi, masalan, yarim, sakkizinchi beshdan to'rtdan uch qism. A umumiy, qo'pol, yoki oddiy kasr (misollar: ${ displaystyle { tfrac {1} {2}}}$ va ${ displaystyle { tfrac {17} {3}}}$) a dan iborat raqamlovchi chiziq ustida (yoki chiziqdan oldin) va nolga teng bo'lmagan holda ko'rsatiladi maxraj, ushbu satr ostida (yoki keyin) ko'rsatilgan. Numeratorlar va maxrajlar bo'lmaydigan kasrlarda ham qo'llaniladi umumiy, shu jumladan aralash kasrlar, murakkab kasrlar va aralash sonlar.

Ijobiy umumiy kasrlarda raqamlovchi va maxraj shunday bo'ladi natural sonlar. Nomerator bir qator teng qismlarni ifodalaydi va maxraj bu qismlarning qanchasi birlik yoki butunlikni tashkil etishini ko'rsatadi. Nominal nolga teng bo'lolmaydi, chunki nol qismlar hech qachon butunlikni tashkil eta olmaydi. Masalan, 3⁄4 kasrda 3-sonli son bizga kasr 3 ta teng qismni, 4-qism esa 4 ta qism butunlikni tashkil etishini aytadi. O'ngdagi rasm tasvirlangan ${ displaystyle { tfrac {3} {4}}}$yoki³⁄₄ tort.

Umumiy kasr - bu raqamni ifodalovchi raqam ratsional raqam. Xuddi shu sonni a shaklida ham ko'rsatish mumkin o‘nli kasr, foiz yoki manfiy ko'rsatkich bilan. Masalan, 0,01, 1% va 10⁻² barchasi 1/100 qismga teng. Butun sonni yashirin maxrajga ega deb hisoblash mumkin (masalan, 7 7/1 ga teng).

Fraktsiyalar uchun boshqa foydalanish vakili qilishdir nisbatlar va bo'linish.^[1] Shunday qilib kasr 3/4 3: 4 nisbatini (qismning butunga nisbati) va 3 ÷ 4 bo'linishni (uchtasi to'rtga bo'linadigan) ifodalash uchun ham foydalanish mumkin. Bo'linishni kasr shaklida ifodalashda qo'llaniladigan nolga teng bo'lmagan qoidalar bu qoidaga misol bo'la oladi nolga bo'linish aniqlanmagan.

Shuningdek, musbat kasrning teskarisini aks ettiruvchi manfiy kasrlarni ham yozishimiz mumkin. Masalan, agar 1/2 yarim dollar foyda anglatadi, keyin -1/2 yarim dollarlik zararni anglatadi. Imzolangan raqamlarni taqsimlash qoidalari tufayli (qisman manfiy musbatga salbiy bo'linishini bildiradi), -1/2, –1/2 va 1/–2 barchasi bir xil kasrni anglatadi - salbiy yarim. Va salbiy bilan bo'linadigan salbiy, ijobiy hosil qilganligi sababli, –1/–2 ijobiy yarmini anglatadi.

Matematikada a / b shaklida ifodalanishi mumkin bo'lgan barcha raqamlar to'plami, bu erda a va b mavjud butun sonlar va b nolga teng emas, u ratsional sonlar to'plami deb nomlanadi va belgi bilan ifodalanadi Q,^[2] qaysi ma'noni anglatadi miqdor. Raqam - bu ushbu shaklda (ya'ni oddiy kasr sifatida) yozilishi mumkin bo'lgan aniq vaqt. Biroq, so'z kasr ratsional sonlar bo'lmagan matematik ifodalarni tavsiflash uchun ham foydalanish mumkin. Ushbu foydalanishga misollar kiradi algebraik kasrlar (algebraik ifodalarning kvotentsiyalari) va o'z ichiga olgan iboralar mantiqsiz raqamlar, kabi √2/ 2 (qarang kvadratning ildizi 2 ) va π / 4 (qarang π ning mantiqsiz ekanligiga dalil ).

Lug'at

Kasrda tasvirlangan teng qismlar soni raqamlovchi (dan.) Lotin raqamli raqam, "counter" yoki "numberer"), va qismlarning turi yoki xilma-xilligi maxraj (dan.) Lotin dēnōminātor, "nom beradigan yoki belgilaydigan narsa").^[3][4] Masalan, kasr⁸⁄₅ sakkiz qismdan iborat bo'lib, ularning har biri "beshinchi" deb nomlangan. Xususida bo'linish, raqamlar mos keladi dividend, va maxraji mos keladi bo'luvchi.

Norasmiy ravishda numerator va maxrajni faqat joylashtirish bilan farqlash mumkin, ammo rasmiy kontekstda ular odatda kasr satri. Fraktsiya chizig'i gorizontal bo'lishi mumkin (kabi 1/3), oblik (2/5 da bo'lgani kabi) yoki diagonali (kabi)⁴⁄₉).^[5] Ushbu belgilar gorizontal chiziq deb nomlanadi; bokiralik, kesma (BIZ ), yoki qon tomir (Buyuk Britaniya ); va kasr satri, solidus,^[6] yoki kasr chizig'i.^{[n 1]} Yilda tipografiya, vertikal ravishda to'plangan kasrlar "nomi bilan ham tanilganuz "yoki"yong'oq kasrlar "va diagonali" kabi "em "yoki" qo'y go'shti fraktsiyalari ", bitta raqamli raqam va maxrajga ega bo'lgan kasr tor qismning ulushini egallashiga asoslanadi. uz kvadrat yoki kengroq em kvadrat.^[5] An'anaviy ravishda matn terish, to'liq fraktsiyani o'z ichiga olgan turdagi parcha (masalan. 1/2) "kasr kasrlari" nomi bilan tanilgan, fraksiyaning faqat bir qismini ifodalaydiganlar esa "bo'lak kasrlar" deb nomlangan.

Ingliz kasrlarining maxrajlari odatda quyidagicha ifodalanadi tartib raqamlari, agar raqam bitta bo'lmasa, ko'plikda. (Masalan,²⁄₅ va³⁄₅ ikkalasi ham "beshlik" qatori sifatida o'qiladi.) Istisnolarga har doim "yarim" yoki "yarmlar" o'qiladigan maxraj 2, 4-qism kiradi, ular muqobil ravishda "chorak" / "choraklar" yoki "" shaklida ifodalanishi mumkin. to'rtinchi "/" to'rtinchi "va maxraji 100, ular muqobil ravishda" yuzinchi "/" yuzinchi "yoki" sifatida ifodalanishi mumkinfoiz ".

Mahraj 1 ga teng bo'lganda, u "yaxlit" so'zlar bilan ifodalanishi mumkin, lekin ko'proq e'tiborga olinmaydi, numerator butun son sifatida o'qiladi. Masalan, 3/1 "uchta" yoki oddiygina "uch" deb ta'riflanishi mumkin. Numerator bitta bo'lsa, uni chiqarib tashlash mumkin ("o'ninchi" yoki "har chorakda" kabi).

Butun kasr bitta kompozitsiya shaklida ifodalanishi mumkin, u holda u defislanadi yoki bitta numeratorga ega bo'lgan bir qancha kasrlar bo'lib, u holda ular bo'lmaydi. (Masalan, "beshdan ikkisi" - bu kasr 2/5 va "ikki beshlik" - bu 2 ta misol sifatida tushunilgan bir xil qism¹⁄₅.) Fraktsiyalar sifat sifatida ishlatilganda doimo tire bilan yozilishi kerak. Shu bilan bir qatorda, kasrni maxrajni "ustidagi" raqam sifatida o'qish bilan, maxrajni "bilan" ifodalash orqali tasvirlash mumkin. asosiy raqam. (Masalan, 3/1 "uchdan bittadan" deb ham ifodalanishi mumkin.) "over" atamasi, hatto a ning chapiga va o'ngiga raqamlar joylashtirilgan solidus fraktsiyalari holatida ham qo'llaniladi. qiyshiq belgi. (Masalan, 1/2 qismi "yarim", "yarim" yoki "ikkitadan bittasi" deb o'qilishi mumkin.) Katta maxrajli kasrlar emas o'nlik vakolatlari ko'pincha shu tarzda amalga oshiriladi (masalan, 1/117 "yuzdan o'n etti" kabi), maxrajlari o'nga bo'linadiganlar odatda odatiy tartibda o'qiladi (masalan, 6/1000000 "olti millioninchi", "olti millioninchi" yoki "olti millioninchi" kabi).

Fraktsiyalarning shakllari

Oddiy, oddiy yoki vulgar kasrlar

A oddiy kasr (a nomi bilan ham tanilgan oddiy kasr yoki vulgar kasr, bu erda vulgar lotincha "umumiy" degan ma'noni anglatadi) a ratsional raqam sifatida yozilgan a/b yoki ${ displaystyle { tfrac {a} {b}}}$, qayerda a va b ikkalasi ham butun sonlar.^[10] Boshqa fraksiyonlarda bo'lgani kabi, maxraj (b) nolga teng bo'lmaydi. Bunga misollar kiradi ${ displaystyle { tfrac {1} {2}}}$, ${ displaystyle - { tfrac {8} {5}}}$, ${ displaystyle { tfrac {-8} {5}}}$va ${ displaystyle { tfrac {8} {- 5}}}$. Ushbu atama dastlab kasrlarning ushbu turini eng kichik seksiya astronomiyada ishlatiladi.^[11]

Umumiy kasrlar ijobiy yoki salbiy bo'lishi mumkin va ular to'g'ri yoki noto'g'ri bo'lishi mumkin (pastga qarang). Murakkab kasrlar, murakkab kasrlar, aralash raqamlar va o'nliklar (quyida ko'rib chiqing) yo'q oddiy kasrlar; ammo, mantiqsiz bo'lmasa, ularni umumiy kasrga baholash mumkin.

• A birlik ulushi 1 raqamiga ega oddiy kasr (masalan, ${ displaystyle { tfrac {1} {7}}}$). Birlik kasrlari, 2 kabi bo'lgani kabi, salbiy ko'rsatkichlar yordamida ham ifodalanishi mumkin⁻¹, bu 1/2 va 2 ni ifodalaydi⁻², bu 1 / (2) ni ifodalaydi²) yoki 1/4.
• A dyadik fraktsiya maxraji a bo'lgan umumiy kasr ikkitasining kuchi, masalan. ${ displaystyle { tfrac {1} {8}} = { tfrac {1} {2 ^ {3}}}}$.

To'g'ri va noto'g'ri fraktsiyalar

Oddiy kasrlarni to'g'ri yoki noto'g'ri deb tasniflash mumkin. Ajratuvchi va maxraj ikkalasi musbat bo'lganda, bo'linuvchi ajratuvchidan kichik bo'lsa, aks holda noto'g'ri bo'lsa, kasr to'g'ri deb nomlanadi.^[12][13] "Noto'g'ri kasr" tushunchasi kech rivojlangan bo'lib, atamalar "kasr" "bo'lak" degan ma'noni anglatadi, shuning uchun to'g'ri kasr 1 dan kam bo'lishi kerak.^[11] Bu XVII asr darsligida tushuntirilgan San'at asoslari.^[14][15]

Umuman olganda, oddiy kasr a deyiladi to'g'ri kasr, agar mutlaq qiymat kasrning birdan qat'iy ravishda kamligi, ya'ni agar fraktsiya -1 dan katta va 1 dan kichik bo'lsa.^[16][17] Bu an noto'g'ri kasryoki ba'zan eng og'ir fraktsiya,^[18] agar kasrning absolyut qiymati 1dan katta yoki unga teng bo'lsa, to'g'ri kasrlarga misollar 2/3, –3/4 va 4/9, noto'g'ri fraktsiyalarga misollar 9/4, -4/3 va 3/3.

O'zaro javoblar va "ko'rinmas maxraj"

The o'zaro kasrning soni va maxraji almashtirilgan boshqa kasr. O'zaro ${ displaystyle { tfrac {3} {7}}}$, masalan ${ displaystyle { tfrac {7} {3}}}$. Kasr va uning o'zaro ko'paytmasi 1 ga teng, shuning uchun o'zaro qiymat multiplikativ teskari kasrning. To'g'ri kasrning o'zaro nisbati noto'g'ri, 1 ga teng bo'lmagan noto'g'ri kasrning o'zaro nisbati (ya'ni, son va maxraj teng emas) to'g'ri kasr.

Kasrning ajratuvchisi va maxraji teng bo'lganda (${ displaystyle { tfrac {7} {7}}}$, masalan), uning qiymati 1 ga teng, shuning uchun kasr noto'g'ri. Uning o'zaro qiymati 1 qiymatiga ega va u ham noto'g'ri.

Har qanday butun sonni kasr sifatida, birinchi raqamni maxraj sifatida yozish mumkin. Masalan, 17 ni quyidagicha yozish mumkin ${ displaystyle { tfrac {17} {1}}}$, bu erda ba'zan 1 deb nomlanadi ko'rinmas maxraj. Shuning uchun noldan tashqari har bir kasr yoki butun son o'zaro ta'sirga ega. Masalan. 17 ning o'zaro bog'liqligi ${ displaystyle { tfrac {1} {17}}}$.

Koeffitsientlar

A nisbat ba'zan kasr shaklida ifodalanishi mumkin bo'lgan ikki yoki undan ortiq sonlar o'rtasidagi munosabatlar. Odatda, har bir guruh o'rtasidagi munosabatni raqamli ravishda ko'rsatib, bir qator narsalar guruhlarga bo'linadi va nisbatda taqqoslanadi. Koeffitsientlar "1-guruhdan 2-guruhga ... guruhga n". Masalan, agar avtoulov parkida 12 ta transport vositasi bo'lsa, ulardan

• 2 oq,
• 6 qizil va
• 4 sariq,

u holda qizil va oq rangdagi sariq mashinalar nisbati 6 dan 2 dan 4 gacha. Sariq mashinalar va oq rangdagi mashinalar nisbati 4 dan 2 gacha va 4: 2 yoki 2: 1 bilan ifodalanishi mumkin.

Koeffitsient ko'pincha butunga nisbati sifatida ifodalanganida kasrga aylanadi. Yuqoridagi misolda sariq mashinalarning uchastkadagi barcha mashinalarga nisbati 4:12 yoki 1: 3 ni tashkil qiladi. Ushbu nisbatlarni kasrga aylantirishimiz va buni aytishimiz mumkin⁴⁄₁₂ avtomobillarning yoki¹⁄₃ lotdagi mashinalar sariq rangda. Shuning uchun, agar kishi tasodifiy uchastkada bitta mashinani tanlagan bo'lsa, unda har uch imkoniyatdan bittasi bor ehtimollik sariq bo'lishini.

O'nli kasrlar va foizlar

A kasr kasr - bu kasr bo'lib, uning maxraji aniq berilmagan, ammo o'nning butun kuchi deb tushuniladi. O'nli kasrlar odatda kasr belgisi yordamida ifodalanadi, shunda nazarda tutilgan qism soniga qarab aniqlanadi raqamlar a o'ng tomonida o‘nli ajratuvchi, ko'rinishi (masalan, nuqta, ko'tarilgan davr (•), vergul) mahalliy tilga bog'liq (masalan, qarang o‘nli ajratuvchi ). Shunday qilib, 0,75 uchun numerator 75 ga, shaffof maxraj ikkinchi kuchga 10 ga teng, ya'ni. 100, chunki kasr ajratuvchisining o'ng tomonida ikkita raqam mavjud. 1 dan katta bo'lgan o'nlik sonlarda (masalan, 3.75), kasr qismi raqamning o'nlikdan o'ng tomonidagi raqamlar bilan ifodalanadi (bu holda 0,75 qiymati bilan). 3.75 ni noto'g'ri kasr sifatida, 375/100 yoki aralash raqam sifatida yozish mumkin, ${ displaystyle 3 { tfrac {75} {100}}}$.

Yordamida o'nlik kasrlarni ham ifodalash mumkin ilmiy yozuv kabi salbiy ko'rsatkichlar bilan 6.023×10⁻⁷, bu 0.0000006023 ni anglatadi. The 10⁻⁷ ning ajratuvchisini ifodalaydi 10⁷. Bo'linish 10⁷ kasrni 7 ta chapga siljitadi.

O'nli ajratuvchidan o'ng tomonda cheksiz ko'p raqamli o'nlik kasrlar cheksiz qator. Masalan, 1/3 = 0.333 ... cheksiz qatorni ifodalaydi 3/10 + 3/100 + 3/1000 + ....

Kasrning yana bir turi bu foiz (Lotin foiz "yuzga" ma'nosini anglatadi,%) belgisi bilan ifodalanadi, unda nazarda tutuvchi har doim 100 ga teng bo'ladi. Shunday qilib, 51% 51/100 degan ma'noni anglatadi. 100 dan yuqori yoki noldan kam foizlar xuddi shu tarzda muomala qilinadi, masalan. 311% 311/100 ga teng, va -27% −27/100 ga teng.

Bilan bog'liq tushunchasi permille yoki ming qism (ppt) ning taxminiy qiymati 1000 ga teng, umumiyroq bo'lsa qismlar boshiga, 75 yilda bo'lgani kabi millionga qismlar (ppm), bu 75 / 1,000,000 nisbati ekanligini anglatadi.

Oddiy kasrlar yoki o'nlik kasrlar ishlatiladimi, ko'pincha ta'm va kontekstga bog'liq. Oddiy kasrlar, odatda, maxraj nisbatan kichik bo'lganda qo'llaniladi. By aqliy hisoblash, buni qilish osonroq ko'paytirmoq Kasrning o'nli ekvivalenti (0.1875) yordamida xuddi shu hisob-kitobni amalga oshirishdan ko'ra 16 dan 3/16 gacha. Va bu ko'proq aniq masalan, 15 ni 1/3 ga ko'paytirish uchun, masalan, uchdan birining o'nli yaqinlashuviga 15ni ko'paytirgandan ko'ra. Pul qiymatlari odatda kasrni 100, ya'ni ikkita o'nlik bilan, masalan, $ 3.75 bilan o'nlik kasrlar sifatida ifodalanadi. Ammo, yuqorida ta'kidlab o'tilganidek, o'nlikdan oldingi ingliz valyutasida shill va pensga ko'pincha kasr shakli berilgan (lekin ma'nosi emas), masalan 3/6 ("uch va oltitani" o'qing) 3 shilling va 6 pens va 3/6 kasr bilan aloqasi yo'q.

Aralash raqamlar

A aralash raqam (shuningdek, a aralash fraksiya yoki aralash raqam) - bu nolga teng bo'lmagan butun son va tegishli kasr yig'indisining an'anaviy belgisi (bir xil belgiga ega). U asosan o'lchovda ishlatiladi: ${ displaystyle 2 { tfrac {3} {16}}}$masalan, dyuym. Ilmiy o'lchovlar deyarli har doim aralash raqamlardan emas, balki o'nlikdan foydalanadi. Yig'ma tegishli "+" kabi ko'rinadigan operatordan foydalanmasdan nazarda tutiladi. Masalan, ikkita butun pirojniy va boshqa tortning to'rtdan uchi haqida gap ketganda, butun son va keklarning kesirli qismini bildiruvchi raqamlar yonma-yon yoziladi. ${ displaystyle 2 { tfrac {3} {4}}}$aniq belgi o'rniga ${ displaystyle 2 + { tfrac {3} {4}}.}$ Salbiy aralash raqamlar, kabi ${ displaystyle -2 { tfrac {3} {4}}}$kabi muomala qilinadi ${ displaystyle - (2 + { tfrac {3} {4}}).}$ A-ning har qanday bunday yig'indisi butun ortiqcha a qism ga o'zgartirilishi mumkin noto'g'ri kasr qoidalarini qo'llash orqali farqli o'laroq miqdorlarni qo'shish.

Ushbu an'ana, rasmiy ravishda, algebra belgilariga zid keladi, ular qo'shni belgilar aniq va ravshan holda infix operatori, mahsulotni bildiradi. Ifoda ${ displaystyle 2x}$, "tushunilgan" operatsiya - bu ko'paytirish. Agar ${ displaystyle x}$ masalan, kasr bilan almashtiriladi ${ displaystyle { tfrac {3} {4}}}$, aralash raqam paydo bo'lishiga yo'l qo'ymaslik uchun "tushunilgan" ko'paytirishni aniq ko'paytirish bilan almashtirish kerak.

Ko'paytirishga mo'ljallangan bo'lsa, ${ displaystyle 2 { tfrac {b} {c}}}$ sifatida yozilishi mumkin

${ displaystyle 2 cdot { tfrac {b} {c}}, quad}$ yoki ${ displaystyle quad 2 times { tfrac {b} {c}}, quad}$ yoki ${ displaystyle quad 2 chap ({ tfrac {b} {c}} o'ng), ; ldots}$

Noto'g'ri kasrni aralash songa quyidagicha o'tkazish mumkin:

1. Foydalanish Evklid bo'linishi (qoldiq bilan bo'linish), sonni maxrajga bo'lish. Misolda, ${ displaystyle { tfrac {11} {4}}}$, 11 ni 4 ga bo'ling. 11 ÷ 4 = 2 qoldiq 3.
2. The miqdor (qoldiqsiz) aralash sonning butun son qismiga aylanadi. Qolgan qismi kasr qismining raqamiga aylanadi. Misolda, 2 butun son qism, 3 qismli qismning raqamidir.
3. Yangi maxraj notekis kasrning maxraji bilan bir xil. Masalan, u 4. Shunday qilib ${ displaystyle { tfrac {11} {4}} = 2 { tfrac {3} {4}}}$.

Tarixiy tushunchalar

Misr kasrlari

An Misr kasrlari masalan, aniq ijobiy birlik fraktsiyalarining yig'indisi ${ displaystyle { tfrac {1} {2}} + { tfrac {1} {3}}}$. Ushbu ta'rif aslida qadimgi misrliklar tashqari barcha kasrlarni ifodalagan ${ displaystyle { tfrac {1} {2}}}$, ${ displaystyle { tfrac {2} {3}}}$ va ${ displaystyle { tfrac {3} {4}}}$ shu tarzda. Har qanday ijobiy ratsional sonni Misr kasrlari sifatida kengaytirish mumkin. Masalan, ${ displaystyle { tfrac {5} {7}}}$ sifatida yozilishi mumkin ${ displaystyle { tfrac {1} {2}} + { tfrac {1} {6}} + { tfrac {1} {21}}.}$ Har qanday ijobiy ratsional sonni birlik kasrlari yig'indisi sifatida cheksiz ko'p usullar bilan yozish mumkin. Yozishning ikkita usuli ${ displaystyle { tfrac {13} {17}}}$ bor ${ displaystyle { tfrac {1} {2}} + { tfrac {1} {4}} + { tfrac {1} {68}}}$ va ${ displaystyle { tfrac {1} {3}} + { tfrac {1} {4}} + { tfrac {1} {6}} + { tfrac {1} {68}}}$.

Murakkab va aralash fraktsiyalar

A murakkab kasr, yoki raqamlovchi, yoki maxraj yoki ikkalasi ham kasr yoki aralash son,^[19][20] kasrlarning bo'linishiga mos keladi. Masalan, ${ displaystyle { frac { tfrac {1} {2}} { tfrac {1} {3}}}}$ va ${ displaystyle { frac {12 { tfrac {3} {4}}} {26}}}$ murakkab kasrlardir. Murakkab kasrni oddiy kasrga kamaytirish uchun eng uzun kasr chizig'ini vakili bo'linma sifatida ko'rib chiqing. Masalan:

${ displaystyle { frac { tfrac {1} {2}} { tfrac {1} {3}}} = { tfrac {1} {2}} times { tfrac {3} {1}} = { tfrac {3} {2}}}$

${ displaystyle { frac {12 { tfrac {3} {4}}} {26}} = 12 { tfrac {3} {4}} cdot { tfrac {1} {26}} = { tfrac {12 cdot 4 + 3} {4}} cdot { tfrac {1} {26}} = { tfrac {51} {4}} cdot { tfrac {1} {26}} = { tfrac {51} {104}}}$

${ displaystyle { frac { tfrac {3} {2}} {5}} = { tfrac {3} {2}} times { tfrac {1} {5}} = { tfrac {3} {10}}}$

${ displaystyle { frac {8} { tfrac {1} {3}}} = 8 times { tfrac {3} {1}} = 24.}$

Agar murakkab kasrda qaysi kasr chiziqlari ustuvorligini aniqlashning o'ziga xos usuli bo'lmasa, bu noaniqlik tufayli bu ifoda noto'g'ri shakllangan. Shunday qilib, 5/10/20/40 matematik ifoda emas, chunki bir nechta mumkin bo'lgan talqinlar, masalan. kabi

${ displaystyle 5 / (10 / (20/40)) = { frac {5} {10 / { tfrac {20} {40}}}} = { frac {1} {4}} quad}$ yoki kabi ${ displaystyle quad (5/10) / (20/40) = { frac { tfrac {5} {10}} { tfrac {20} {40}}} = 1}$

A aralash fraksiya kasrning bir qismi yoki bu so'z bilan bog'liq bo'lgan har qanday sonli kasr ning,^[19][20] kasrlarni ko'paytirishga mos keladi. Murakkab qismni oddiy kasrga kamaytirish uchun faqat ko'paytirishni bajaring (bo'limiga qarang.) ko'paytirish ). Masalan, ${ displaystyle { tfrac {3} {4}}}$ ning ${ displaystyle { tfrac {5} {7}}}$ ga mos keladigan birikma kasr hisoblanadi ${ displaystyle { tfrac {3} {4}} times { tfrac {5} {7}} = { tfrac {15} {28}}}$. Murakkab kasr va murakkab kasr atamalari bir-biri bilan chambarchas bog'liq va ba'zida biri ikkinchisining sinonimi sifatida ishlatiladi. (Masalan, aralash fraktsiya ${ displaystyle { tfrac {3} {4}} times { tfrac {5} {7}}}$ murakkab kasrga tengdir ${ displaystyle { tfrac {3/4} {7/5}}}$.)

Shunga qaramay, "murakkab fraktsiya" va "aralash fraktsiya" ikkalasi ham eskirgan hisoblanadi^[21] va hozirda biron bir aniq ma'noda ishlatilmaydi, qisman hatto bir-biriga sinonim sifatida qabul qilinadi^[22] yoki aralash raqamlar uchun.^[23] Ular texnik atamalar sifatida ma'nosini yo'qotdi va "murakkab" va "birikma" atributlari har kuni "qismlardan iborat" ma'nosida ishlatilishga moyil.

Kasrlar bilan hisoblash

Butun sonlar singari, kasrlar ham itoat etadi kommutativ, assotsiativ va tarqatuvchi qonunlar va qarshi qoida nolga bo'linish.

Ekvivalent kasrlar

Kasrning sonini va maxrajini bir xil (nolga teng bo'lmagan) songa ko'paytirish natijasida dastlabki kasrga teng bo'lgan kasr olinadi. Bu to'g'ri, chunki nolga teng bo'lmagan har qanday raqam uchun ${ displaystyle n}$, kasr ${ displaystyle { tfrac {n} {n}} = 1}$. Shuning uchun, tomonidan ko'paytiriladi ${ displaystyle { tfrac {n} {n}}}$biriga ko'paytirilishga teng va biriga ko'paytiriladigan har qanday son asl son bilan bir xil qiymatga ega. Misol tariqasida, kasrdan boshlang ${ displaystyle { tfrac {1} {2}}}$. Numerator va maxraj ikkalasini 2 ga ko'paytirganda, natija bo'ladi ${ displaystyle { tfrac {2} {4}}}$, bilan bir xil qiymatga ega (0,5) ${ displaystyle { tfrac {1} {2}}}$. Buni vizual ravishda tasavvur qilish uchun tortni to'rt qismga bo'linishini tasavvur qiling; ikkitasi birgalikda (${ displaystyle { tfrac {2} {4}}}$) pirojniyning yarmini tashkil eting (${ displaystyle { tfrac {1} {2}}}$).

Fraktsiyalarni soddalashtirish (kamaytirish)

Kasrning raqamini va maxrajini bir xil nolga teng bo'lmagan songa bo'lish ham ekvivalent kasrni hosil qiladi. Agar kasrning ajratuvchisi va maxraji ikkalasi ham 1dan kattaroq songa bo'linadigan bo'lsa (koeffitsient deb ataladi), u holda kasrni kichikroq va kichikroq bo'linmaga ega bo'lgan teng qismga kamaytirish mumkin. Buning uchun eng katta umumiy omil aniqlanadi va ikkala raqamlovchi va maxraj shu omilga bo'linadi. Masalan, agar kasrning ikkala numeratori va maxraji bo'lsa ${ displaystyle { tfrac {a} {b}}}$bo'linadi ${ displaystyle c,}$ keyin ularni shunday yozish mumkin ${ displaystyle a = cd}$ va ${ displaystyle b = ce,}$ shuning uchun kasr bo'ladi ${ displaystyle { tfrac {cd} {ce}}}$, ikkala sonni va maxrajni ikkiga bo'lish orqali kamaytirish mumkin ${ displaystyle c}$ kamaytirilgan kasrni berish ${ displaystyle { tfrac {d} {e}}.}$

Agar raqamlovchi va maxraj 1-dan katta koeffitsientni taqsimlamasa, u holda kasr deyiladi qisqartirilmaydi, eng past ma'noda yoki oddiy so'zlar bilan. Masalan, ${ displaystyle { tfrac {3} {9}}}$eng past ma'noda emas, chunki 3 va 9 ikkalasini ham 3 ga bo'linishi mumkin, aksincha, ${ displaystyle { tfrac {3} {8}}}$ bu eng past ma'noda - 3 ga va 8 ga teng keladigan yagona musbat butun son 1 ga teng.

Ushbu qoidalar yordamida biz buni ko'rsata olamiz ${ displaystyle { tfrac {5} {10}}}$= ${ displaystyle { tfrac {1} {2}}}$= ${ displaystyle { tfrac {10} {20}}}$= ${ displaystyle { tfrac {50} {100}}}$.

Yana bir misol, 63 va 462 ning eng katta umumiy bo'luvchisi 21 bo'lganligi sababli, kasr ${ displaystyle { tfrac {63} {462}}}$numerator va maxrajni 21 ga bo'lish orqali eng past darajaga tushirish mumkin:

${ displaystyle { tfrac {63} {462}} = { tfrac {63 div 21} {462 div 21}} = { tfrac {3} {22}}}$

The Evklid algoritmi har qanday ikkita musbat butun sonning eng katta umumiy bo'luvchisini topish usulini beradi.

Fraktsiyalarni taqqoslash

Bir xil musbat maxrajga ega bo'lgan fraktsiyalarni taqqoslash, raqamlarni taqqoslash bilan bir xil natija beradi:

${ displaystyle { tfrac {3} {4}}> { tfrac {2} {4}}}$ chunki 3 > 2va teng maxrajlar ${ displaystyle 4}$ ijobiy.

Agar teng maxrajlar manfiy bo'lsa, unda kasrlar uchun numeratorlarni taqqoslashning teskari natijasi:

${ displaystyle { tfrac {3} {- 4}} <{ tfrac {2} {- 4}} { text {because}} { tfrac {a} {- b}} = { tfrac {- a} {b}} { text {va}} - 3 <-2.}$

Agar ikkita musbat kasrning raqamlari bir xil bo'lsa, unda kichikroq bo'linma bo'lgan qism katta songa teng bo'ladi. Agar butunlik teng bo'laklarga bo'linsa, butunlikni tashkil qilish uchun kamroq teng bo'laklar kerak bo'lsa, unda har bir bo'lak kattaroq bo'lishi kerak. Ikkita musbat kasrlar bir xil raqamga ega bo'lganda, ular bir xil sonli qismlarni ifodalaydi, lekin kichikroq bo'linadigan qismda qismlar kattaroq bo'ladi.

Kasrlarni har xil raqamlar va maxrajlar bilan taqqoslash usullaridan biri bu umumiy maxrajni topishdir. Taqqoslash uchun ${ displaystyle { tfrac {a} {b}}}$ va ${ displaystyle { tfrac {c} {d}}}$, ular aylantiriladi ${ displaystyle { tfrac {a cdot d} {b cdot d}}}$ va ${ displaystyle { tfrac {b cdot c} {b cdot d}}}$ (bu erda nuqta ko'paytishni anglatadi va × ga muqobil belgidir). Keyin bd umumiy maxraj va sonlar reklama va mil taqqoslash mumkin. Fraktsiyalarni taqqoslash uchun umumiy maxrajning qiymatini aniqlash shart emas - shunchaki taqqoslash mumkin reklama va mil, baholamasdan bd, masalan, taqqoslash ${ displaystyle { tfrac {2} {3}}}$ ? ${ displaystyle { tfrac {1} {2}}}$ beradi ${ displaystyle { tfrac {4} {6}}> { tfrac {3} {6}}}$.

Ko'proq mehnatsevar savol uchun ${ displaystyle { tfrac {5} {18}}}$ ? ${ displaystyle { tfrac {4} {17}},}$ har bir kasrning yuqori va pastki qismlarini boshqa kasrning maxrajiga ko'paytiring, hosil bo'ladigan umumiy maxrajni oling ${ displaystyle { tfrac {5 times 17} {18 times 17}}}$ ? ${ displaystyle { tfrac {18 times 4} {18 times 17}}}$. Hisoblash shart emas ${ displaystyle 18 marta 17}$ - faqat raqamlarni taqqoslash kerak. 5 × 17 (= 85) 4 × 18 (= 72) dan katta bo'lgani uchun taqqoslash natijasi ${ displaystyle { tfrac {5} {18}}> { tfrac {4} {17}}}$.

Har qanday manfiy son, shu jumladan manfiy kasrlar noldan kichik, musbat kasrlar bilan birga har bir musbat son noldan katta bo'lgani uchun, har qanday manfiy kasr har qanday musbat kasrdan kichik ekanligi kelib chiqadi. Bu yuqoridagi qoidalar bilan birgalikda barcha mumkin bo'lgan kasrlarni solishtirishga imkon beradi.

Qo'shish

Qo'shishning birinchi qoidasi shundaki, faqat shunga o'xshash miqdorlarni qo'shish mumkin; masalan, har xil miqdordagi choraklar. Miqdorlardan farqli o'laroq, masalan, choraklarga uchdan birini qo'shish, avval quyida tasvirlanganidek, yoqadigan miqdorlarga aylantirilishi kerak: Tasavvur qiling, cho'ntak ikki chorakdan iborat, boshqa cho'ntak chorakdan iborat; jami besh chorak bor. To'rt chorak bir (dollar) ga teng bo'lganligi sababli, uni quyidagicha ifodalash mumkin:

${ displaystyle { tfrac {2} {4}} + { tfrac {3} {4}} = { tfrac {5} {4}} = 1 { tfrac {1} {4}}}$.

Agar ${ displaystyle { tfrac {1} {2}}}$ pirojniy qo'shilishi kerak ${ displaystyle { tfrac {1} {4}}}$ pirojniyning bo'laklarini taqqoslash mumkin bo'lgan miqdorlarga, masalan, tort-sakkizinchi yoki to'rtdan to'rt qismga aylantirish kerak.

Miqdoridan farqli o'laroq qo'shiladi

O'ziga o'xshamaydigan miqdorlarni (masalan, chorak va uchdan bir qismi) o'z ichiga olgan fraktsiyalarni qo'shish uchun barcha miqdorlarni yoqadigan miqdorlarga o'tkazish kerak. Konvertatsiya qilish uchun tanlangan kasr turini ishlab chiqish oson; shunchaki har bir kasrning ikkita maxrajini (pastki raqami) ko'paytiring. Agar butun son bo'lsa, amal qiling ko'rinmas maxraj ${ displaystyle 1.}$

Choraklarni uchdan biriga qo'shish uchun ikkala fraktsiya turi o'n ikkinchi qismga aylantiriladi, shunday qilib:

${ displaystyle { frac {1} {4}} + { frac {1} {3}} = { frac {1 times 3} {4 times 3}} + { frac {1 marta 4} {3 times 4}} = { frac {3} {12}} + { frac {4} {12}} = { frac {7} {12}}.}$

Quyidagi ikkita miqdorni qo'shishni o'ylab ko'ring:

${ displaystyle { frac {3} {5}} + { frac {2} {3}}}$

Birinchidan, aylantiring ${ displaystyle { tfrac {3} {5}}}$ ikkala raqamni va maxrajni uchga ko'paytirish orqali o'n beshinchi qismga: ${ displaystyle { tfrac {3} {5}} times { tfrac {3} {3}} = { tfrac {9} {15}}}$. Beri ${ displaystyle { tfrac {3} {3}}}$ 1 ga teng, ko'paytirish ${ displaystyle { tfrac {3} {3}}}$ kasr qiymatini o'zgartirmaydi.

Ikkinchidan, aylantirish ${ displaystyle { tfrac {2} {3}}}$ ikkala raqamni va maxrajni beshga ko'paytirish orqali o'n beshinchi qismga: ${ displaystyle { tfrac {2} {3}} times { tfrac {5} {5}} = { tfrac {10} {15}}}$.

Endi buni ko'rish mumkin:

${ displaystyle { frac {3} {5}} + { frac {2} {3}}}$

ga teng:

${ displaystyle { frac {9} {15}} + { frac {10} {15}} = { frac {19} {15}} = 1 { frac {4} {15}}}$

Ushbu usul algebraik tarzda ifodalanishi mumkin:

${ displaystyle { frac {a} {b}} + { frac {c} {d}} = { frac {ad + cb} {bd}}}$

Ushbu algebraik usul har doim ham ishlaydi va shu bilan oddiy kasrlar yig'indisi yana oddiy kasr bo'lishiga kafolat beradi. Ammo, agar bitta maxrajda umumiy koeffitsient mavjud bo'lsa, bu hosilaga qaraganda kichikroq maxrajdan foydalanish mumkin. Masalan, qo'shganda ${ displaystyle { tfrac {3} {4}}}$ va ${ displaystyle { tfrac {5} {6}}}$ yagona maxrajlar umumiy omilga ega ${ displaystyle 2,}$ va shuning uchun maxraj 24 (4 × 6) o'rniga ikkiga bo'lingan maxraj 12 ishlatilishi mumkin, bu nafaqat natijadagi maxrajni kamaytiradi, balki numeratordagi omillarni ham kamaytiradi.

${ displaystyle { begin {aligned} { frac {3} {4}} + { frac {5} {6}} & = { frac {3 cdot 6} {4 cdot 6}} + { frac {4 cdot 5} {4 cdot 6}} = { frac {18} {24}} + { frac {20} {24}} & = { frac {19} {12}} & = { frac {3 cdot 3} {4 cdot 3}} + { frac {2 cdot 5} {2 cdot 6}} = { frac {9} {12}} + { frac {10} {12}} & = { frac {19} {12}} end {aligned}}}$

Mumkin bo'lgan eng kichik bo'linuvchi eng kichik umumiy ko'plik Bitta maxrajlarning soni, bu yodlovchilarning ko'pliklarini yagona maxrajlarning barcha umumiy omillariga bo'lishidan kelib chiqadi. Bu eng kichik umumiy maxraj deyiladi.

Chiqarish

Kasrlarni ayirish jarayoni, mohiyatan, ularni qo'shish bilan bir xil: umumiy maxrajni toping va tanlangan umumiy maxraj bilan har bir kasrni teng qismga o'zgartiring. Hosil bo'lgan kasr shu maxrajga ega bo'ladi va uning raqamlagichi asl kasrlar sonini ayirish natijasi bo'ladi. Masalan; misol uchun,

${ displaystyle { tfrac {2} {3}} - { tfrac {1} {2}} = { tfrac {4} {6}} - { tfrac {3} {6}} = { tfrac {1} {6}}}$

Ko'paytirish

Kasrni boshqa kasrga ko'paytirish

Kasrlarni ko'paytirish uchun sonlarni ko'paytiring va bo'linmalarni ko'paytiring. Shunday qilib:

${ displaystyle { tfrac {2} {3}} times { tfrac {3} {4}} = { tfrac {6} {12}}}$

Jarayonni tushuntirish uchun chorakning uchdan bir qismini ko'rib chiqing. Kek misolidan foydalanib, agar bir xil o'lchamdagi uchta kichik bo'lak to'rtdan birini, to'rtdan to'rt qismi butunni tashkil etsa, shu kichik, teng bo'laklarning o'n ikkitasi butunlikni tashkil qiladi. Shuning uchun, chorakning uchdan bir qismi o'n ikkinchi. Endi raqamlarni ko'rib chiqing. Birinchi fraktsiya, uchdan ikki qismi, uchdan biriga nisbatan ikki baravar katta. Chorakning uchdan bir qismi o'n ikkidan bir qism bo'lganligi sababli, chorakning uchdan ikki qismi o'n ikki qismdan iborat. Ikkinchi fraktsiya, to'rtdan uch qismi, to'rtdan biriga nisbatan uch baravar katta, shuning uchun uch chorakning uchdan ikki qismi chorakning uchdan ikki qismiga nisbatan uch baravar katta. Shunday qilib uchdan ikki uchdan uch chorak olti o'n ikkinchi.

Kasrlarni ko'paytirish uchun qisqartirish "bekor qilish" deb nomlanadi. Ko'paytirish paytida javob eng past ko'rsatkichlarga kamaytiriladi. Masalan:

${ displaystyle { tfrac {2} {3}} times { tfrac {3} {4}} = { tfrac {{ bekor qilish {2}} ^ {~ 1}} {{ bekor qilish {3} } ^ {~ 1}}} marta { tfrac {{ bekor qilish {3}} ^ {~ 1}} {{ bekor qilish {4}} ^ {~ 2}}} = { tfrac {1} { 1}} times { tfrac {1} {2}} = { tfrac {1} {2}}}$

Ikkisi umumiydir omil ikkala chap kasrning sonida va o'ngning maxrajida va ikkalasidan ham bo'linadi. Uchtasi - chap chegara va o'ng sonning umumiy omili va ikkalasidan ham bo'linadi.

Kasrni butun songa ko'paytirish

Butun sonni o'zi 1 ga bo'lingan holda qayta yozish mumkin bo'lganligi sababli, odatdagi kasrlarni ko'paytirish qoidalari amal qilishi mumkin.

${ displaystyle 6 times { tfrac {3} {4}} = { tfrac {6} {1}} times { tfrac {3} {4}} = { tfrac {18} {4}} }$

Ushbu usul ishlaydi, chunki 6/1 fraktsiya oltita teng qismni anglatadi, ularning har biri butundir.

Aralash raqamlarni ko'paytirish

Aralash sonlarni ko'paytirishda aralash sonni noto'g'ri kasrga aylantirish afzal deb hisoblanadi.^[24] Masalan:

${ displaystyle 3 times 2 { tfrac {3} {4}} = 3 times chap ({ tfrac {8} {4}} + { tfrac {3} {4}} right) = 3 times { tfrac {11} {4}} = { tfrac {33} {4}} = 8 { tfrac {1} {4}}}$

Boshqa so'zlar bilan aytganda, ${ displaystyle 2 { tfrac {3} {4}}}$ bilan bir xil ${ displaystyle { tfrac {8} {4}} + { tfrac {3} {4}}}$, jami 11 chorakni tashkil etadi (chunki har biri chorakka bo'lingan 2 ta pirojnoe jami 8 chorakni tashkil qiladi) va 33 chorak ${ displaystyle 8 { tfrac {1} {4}}}$, chunki har biri to'rtdan qilingan 8 ta pirojnoe jami 32 chorakni tashkil qiladi.

Bo'lim

Kasrni butun songa bo'lish uchun siz raqamni raqamga bo'lishingiz mumkin, agar u raqamga teng bo'lsa yoki maxrajni songa ko'paytirsangiz. Masalan, ${ displaystyle { tfrac {10} {3}} div 5}$ teng ${ displaystyle { tfrac {2} {3}}}$ va tengdir ${ displaystyle { tfrac {10} {3 cdot 5}} = { tfrac {10} {15}}}$ga kamaytiradi ${ displaystyle { tfrac {2} {3}}}$. Raqamni kasrga bo'lish uchun ushbu sonni ga ko'paytiring o'zaro shu kasrning. Shunday qilib, ${ displaystyle { tfrac {1} {2}} div { tfrac {3} {4}} = { tfrac {1} {2}} times { tfrac {4} {3}} = { tfrac {1 cdot 4} {2 cdot 3}} = { tfrac {2} {3}}}$.

O'nli va kasrlar o'rtasida konvertatsiya qilish

Umumiy kasrni o‘nli kasrga almashtirish uchun sonning o‘nlik ko‘rinishlarini maxrajga bo‘linishi bilan uzun bo‘ling (bu idiomatik ravishda "maxrajni raqamga ajrating" deb ham ifodalangan) va javobni kerakli aniqlikda aylantiring. Masalan, o'zgartirish uchun¹⁄₄ o‘nli kasrga bo‘ling ${ displaystyle 1.00}$ tomonidan ${ displaystyle 4}$ ("${ displaystyle 4}$ ichiga ${ displaystyle 1.00}$") olish uchun ${ displaystyle 0.25}$. O'zgartirish uchun¹⁄₃ o‘nli kasrga bo‘ling ${ displaystyle 1.000 ...}$ tomonidan ${ displaystyle 3}$ ("${ displaystyle 3}$ ichiga ${displaystyle 1.0000...}$"), and stop when the desired accuracy is obtained, e.g., at ${ displaystyle 4}$ decimals with ${displaystyle 0.3333}$. The fraction ​¹⁄₄ can be written exactly with two decimal digits, while the fraction ​¹⁄₃ cannot be written exactly as a decimal with a finite number of digits. To change a decimal to a fraction, write in the denominator a ${ displaystyle 1}$ followed by as many zeroes as there are digits to the right of the decimal point, and write in the numerator all the digits of the original decimal, just omitting the decimal point. Shunday qilib ${displaystyle 12.3456={ frac {123456}{10000}}.}$

Converting repeating decimals to fractions

Decimal numbers, while arguably more useful to work with when performing calculations, sometimes lack the precision that common fractions have. Sometimes an infinite repeating decimal is required to reach the same precision. Thus, it is often useful to convert repeating decimals into fractions.

Afzal^{[kim tomonidan? ]} way to indicate a repeating decimal is to place a bar (known as a vinculum ) over the digits that repeat, for example 0.789 = 0.789789789... For repeating patterns where the repeating pattern begins immediately after the decimal point, a simple division of the pattern by the same number of nines as numbers it has will suffice. Masalan:

0.5 = 5/9

0.62 = 62/99

0.264 = 264/999

0.6291 = 6291/9999

Bo'lgan holatda etakchi nollar precede the pattern, the nines are suffixed by the same number of trailing zeros:

0.05 = 5/90

0.000392 = 392/999000

0.0012 = 12/9900

In case a non-repeating set of decimals precede the pattern (such as 0.1523987), we can write it as the sum of the non-repeating and repeating parts, respectively:

0.1523 + 0.0000987

Then, convert both parts to fractions, and add them using the methods described above:

1523 / 10000 + 987 / 9990000 = 1522464 / 9990000

Alternatively, algebra can be used, such as below:

1. Ruxsat bering x = the repeating decimal:

   x = 0.1523987

2. Multiply both sides by the power of 10 just great enough (in this case 10⁴) to move the decimal point just before the repeating part of the decimal number:

   10,000x = 1,523.987

3. Multiply both sides by the power of 10 (in this case 10³) that is the same as the number of places that repeat:

   10,000,000x = 1,523,987.987

4. Subtract the two equations from each other (if a = b va v = d, keyin a − v = b − d):

   10,000,000x − 10,000x = 1,523,987.987 − 1,523.987

5. Continue the subtraction operation to clear the repeating decimal:

   9,990,000x = 1,523,987 − 1,523

   9,990,000x = 1,522,464

6. Divide both sides by 9,990,000 to represent x as a fraction

   x = 1522464 / 9990000

Fractions in abstract mathematics

In addition to being of great practical importance, fractions are also studied by mathematicians, who check that the rules for fractions given above are consistent and reliable. Mathematicians define a fraction as an ordered pair ${ displaystyle (a, b)}$ ning butun sonlar ${ displaystyle a}$va ${displaystyle b eq 0,}$ for which the operations qo'shimcha, ayirish, ko'paytirish va bo'linish quyidagicha belgilanadi:^[25]

${displaystyle (a,b)+(c,d)=(ad+bc,bd),}$

${displaystyle (a,b)-(c,d)=(ad-bc,bd),}$

${displaystyle (a,b)cdot (c,d)=(ac,bd)}$

${displaystyle (a,b)div (c,d)=(ad,bc)quad ({ ext{with, additionally, }}c eq 0)}$

These definitions agree in every case with the definitions given above; only the notation is different. Alternatively, instead of defining subtraction and division as operations, the "inverse" fractions with respect to addition and multiplication might be defined as:

${displaystyle {egin{aligned}-(a,b)&=(-a,b)&&{ ext{additive inverse fractions,}}&&&{ ext{with }}(0,b){ ext{ as additive unities, and}}(a,b)^{-1}&=(b,a)&&{ ext{multiplicative inverse fractions, for }}a eq 0,&&&{ ext{with }}(b,b){ ext{ as multiplicative unities}}.end{aligned}}}$

Bundan tashqari, munosabat, specified as

${displaystyle (a,b)sim (c,d)quad iff quad ad=bc,}$

bu ekvivalentlik munosabati of fractions. Each fraction from one equivalence class may be considered as a representative for the whole class, and each whole class may be considered as one abstract fraction. This equivalence is preserved by the above defined operations, i.e., the results of operating on fractions are independent of the selection of representatives from their equivalence class. Formally, for addition of fractions

${displaystyle (a,b)sim (a',b')quad }$ va ${displaystyle quad (c,d)sim (c',d')quad }$ nazarda tutmoq

${displaystyle ((a,b)+(c,d))sim ((a',b')+(c',d'))}$

and similarly for the other operations.

In the case of fractions of integers, the fractions a/b bilan a va b koprime va b > 0 are often taken as uniquely determined representatives for their teng fractions, which are considered to be the bir xil rational number. This way the fractions of integers make up the field of the rational numbers.

Umuman olganda, a va b may be elements of any ajralmas domen R, in which case a fraction is an element of the field of fractions ning R. Masalan, polinomlar in one indeterminate, with coefficients from some integral domain D., are themselves an integral domain, call it P. Shunday qilib a va b elementlari P, the generated field of fractions maydonidir rational fractions (also known as the field of ratsional funktsiyalar ).

Algebraic fractions

An algebraic fraction is the indicated miqdor ikkitadan algebraic expressions. As with fractions of integers, the denominator of an algebraic fraction cannot be zero. Two examples of algebraic fractions are ${displaystyle {frac {3x}{x^{2}+2x-3}}}$ va ${displaystyle {frac {sqrt {x+2}}{x^{2}-3}}}$. Algebraic fractions are subject to the same maydon properties as arithmetic fractions.

If the numerator and the denominator are polinomlar, kabi ${displaystyle {frac {3x}{x^{2}+2x-3}}}$, the algebraic fraction is called a rational fraction (yoki rational expression). An irrational fraction is one that is not rational, as, for example, one that contains the variable under a fractional exponent or root, as in ${displaystyle {frac {sqrt {x+2}}{x^{2}-3}}}$.

The terminology used to describe algebraic fractions is similar to that used for ordinary fractions. For example, an algebraic fraction is in lowest terms if the only factors common to the numerator and the denominator are 1 and −1. An algebraic fraction whose numerator or denominator, or both, contain a fraction, such as ${displaystyle {frac {1+{ frac {1}{x}}}{1-{ frac {1}{x}}}}}$, is called a complex fraction.

The field of rational numbers is the field of fractions of the integers, while the integers themselves are not a field but rather an ajralmas domen. Xuddi shunday, rational fractions with coefficients in a maydon form the field of fractions of polynomials with coefficient in that field. Considering the rational fractions with real coefficients, radical expressions representing numbers, such as ${displaystyle extstyle {sqrt {2}}/2,}$ are also rational fractions, as are a transandantal raqamlar kabi ${ extstyle pi /2,}$ since all of ${displaystyle {sqrt {2}},pi ,}$ va ${ displaystyle 2}$ bor haqiqiy raqamlar, and thus considered as coefficients. These same numbers, however, are not rational fractions with tamsayı coefficients.

Atama partial fraction is used when decomposing rational fractions into sums of simpler fractions. For example, the rational fraction ${displaystyle {frac {2x}{x^{2}-1}}}$ can be decomposed as the sum of two fractions: ${displaystyle {frac {1}{x+1}}+{frac {1}{x-1}}.}$ This is useful for the computation of antidiviv vositalar ning ratsional funktsiyalar (qarang partial fraction decomposition for more).

Radical expressions

A fraction may also contain radikallar in the numerator and/or the denominator. If the denominator contains radicals, it can be helpful to ratsionalizatsiya qilish it (compare Simplified form of a radical expression ), especially if further operations, such as adding or comparing that fraction to another, are to be carried out. It is also more convenient if division is to be done manually. When the denominator is a monomial square root, it can be rationalized by multiplying both the top and the bottom of the fraction by the denominator:

${displaystyle {frac {3}{sqrt {7}}}={frac {3}{sqrt {7}}}cdot {frac {sqrt {7}}{sqrt {7}}}={frac {3{sqrt {7}}}{7}}}$

The process of rationalization of binomial denominators involves multiplying the top and the bottom of a fraction by the birlashtirmoq of the denominator so that the denominator becomes a rational number. Masalan:

${displaystyle {frac {3}{3-2{sqrt {5}}}}={frac {3}{3-2{sqrt {5}}}}cdot {frac {3+2{sqrt {5}}}{3+2{sqrt {5}}}}={frac {3(3+2{sqrt {5}})}{{3}^{2}-(2{sqrt {5}})^{2}}}={frac {3(3+2{sqrt {5}})}{9-20}}=-{frac {9+6{sqrt {5}}}{11}}}$

${displaystyle {frac {3}{3+2{sqrt {5}}}}={frac {3}{3+2{sqrt {5}}}}cdot {frac {3-2{sqrt {5}}}{3-2{sqrt {5}}}}={frac {3(3-2{sqrt {5}})}{{3}^{2}-(2{sqrt {5}})^{2}}}={frac {3(3-2{sqrt {5}})}{9-20}}=-{frac {9-6{sqrt {5}}}{11}}}$

Even if this process results in the numerator being irrational, like in the examples above, the process may still facilitate subsequent manipulations by reducing the number of irrationals one has to work with in the denominator.

Typographical variations

In computer displays and tipografiya, simple fractions are sometimes printed as a single character, e.g. ½ (yarim ). Maqolaga qarang Number Forms for information on doing this in Unicode.

Scientific publishing distinguishes four ways to set fractions, together with guidelines on use:^[26]

• special fractions: fractions that are presented as a single character with a slanted bar, with roughly the same height and width as other characters in the text. Generally used for simple fractions, such as: ½, ⅓, ⅔, ¼, and ¾. Since the numerals are smaller, legibility can be an issue, especially for small-sized fonts. These are not used in modern mathematical notation, but in other contexts.
• case fractions: similar to special fractions, these are rendered as a single typographical character, but with a horizontal bar, thus making them tik. Misol bo'lishi mumkin ${displaystyle { frac {1}{2}}}$, but rendered with the same height as other characters. Some sources include all rendering of fractions as case fractions if they take only one typographical space, regardless of the direction of the bar.^[27]
• shiling yoki solidus fractions: 1/2, so called because this notation was used for pre-decimal British currency (£ SD ), as in 2/6 for a half crown, meaning two shillings and six pence. While the notation "two shillings and six pence" did not represent a fraction, the forward slash is now used in fractions, especially for fractions inline with prose (rather than displayed), to avoid uneven lines. It is also used for fractions within fractions (complex fractions ) or within exponents to increase legibility. Fractions written this way, also known as piece fractions,^[28] are written all on one typographical line, but take 3 or more typographical spaces.
• built-up fractions: ${displaystyle {frac {1}{2}}}$. This notation uses two or more lines of ordinary text, and results in a variation in spacing between lines when included within other text. While large and legible, these can be disruptive, particularly for simple fractions or within complex fractions.

Tarix

The earliest fractions were reciprocals ning butun sonlar: ancient symbols representing one part of two, one part of three, one part of four, and so on.^[29] The Misrliklar ishlatilgan Egyptian fractions v. 1000 Miloddan avvalgi. About 4000 years ago, Egyptians divided with fractions using slightly different methods. They used least common multiples with unit fractions. Their methods gave the same answer as modern methods.^[30] The Egyptians also had a different notation for dyadic fractions ichida Axmim yog'och taxta va bir nechta Rind matematik papirus muammolar.

The Yunonlar used unit fractions and (later) davom etgan kasrlar. Izdoshlar ning Yunoncha faylasuf Pifagoralar (v. 530 Miloddan avvalgi) discovered that the square root of two cannot be expressed as a fraction of integers. (This is commonly though probably erroneously ascribed to Hippas ning Metapontum, who is said to have been executed for revealing this fact.) In 150 Miloddan avvalgi Jain mathematicians in Hindiston wrote the "Sthananga Sutra ", which contains work on the theory of numbers, arithmetical operations, and operations with fractions.

A modern expression of fractions known as bhinnarasi seems to have originated in India in the work of Aryabhatta (v. Mil 500),^{[iqtibos kerak ]} Braxmagupta (v. 628) va Bxaskara (v. 1150).^[31] Their works form fractions by placing the numerators (Sanskritcha: amsa) over the denominators (cheda), but without a bar between them.^[31] Yilda Sanskrit adabiyoti, fractions were always expressed as an addition to or subtraction from an integer.^{[iqtibos kerak ]} The integer was written on one line and the fraction in its two parts on the next line. If the fraction was marked by a small circle ⟨०⟩ or cross ⟨+⟩, it is subtracted from the integer; if no such sign appears, it is understood to be added. Masalan, Bhaskara I yozadi:^[32]

६        १        २

१        १        १_०

४        ५        ९

which is the equivalent of

6        1        2

1        1        −1

4        5        9

and would be written in modern notation as 61/4, 11/5, and 2 − 1/9 (i.e., 18/9).

The horizontal fraction bar is first attested in the work of Al-Hassār (fl. 1200),^[31] a Musulmon matematik dan Fez, Marokash, kim ixtisoslashgan Islom meros huquqshunosligi. In his discussion he writes, "... for example, if you are told to write three-fifths and a third of a fifth, write thus, ${displaystyle {frac {3quad 1}{5quad 3}}}$."^[33] The same fractional notation—with the fraction given before the integer^[31]—appears soon after in the work of Leonardo Fibonacci XIII asrda.^[34]

In discussing the origins of decimal fractions, Dirk Yan Struik aytadi:^[35]

"The introduction of decimal fractions as a common computational practice can be dated back to the Flamancha risola De Thiende, da chop etilgan Leyden in 1585, together with a French translation, La Disme, by the Flemish mathematician Simon Stevin (1548–1620), then settled in the Northern Gollandiya. It is true that decimal fractions were used by the Xitoy many centuries before Stevin and that the Persian astronomer Al-Kāshī used both decimal and eng kichik fractions with great ease in his Key to arithmetic (Samarqand, early fifteenth century)."^[36]

Da Fors tili matematik Jamshid al-Koshiy claimed to have discovered decimal fractions himself in the 15th century, J. Lennart Berggren notes that he was mistaken, as decimal fractions were first used five centuries before him by the Bag'dodiy matematik Abu'l-Hasan al-Uqlidisiy as early as the 10th century.^{[37][n 2]}

In formal education

Pedagogical tools

Yilda boshlang'ich maktablari, fractions have been demonstrated through Oshxona majmuasi, Fraksiya panjaralari, fraction strips, fraction circles, paper (for folding or cutting), pattern blocks, pie-shaped pieces, plastic rectangles, grid paper, dot paper, geoboards, counters and computer software.

Documents for teachers

Several states in the United States have adopted learning trajectories from the Umumiy asosiy davlat standartlari tashabbusi 's guidelines for mathematics education. Aside from sequencing the learning of fractions and operations with fractions, the document provides the following definition of a fraction: "A number expressible in the form ​^{${ displaystyle a}$}⁄_{${ displaystyle b}$} qayerda ${ displaystyle a}$ is a whole number and ${ displaystyle b}$ is a positive whole number. (So'z kasr in these standards always refers to a non-negative number.)"^[39] The document itself also refers to negative fractions.

Shuningdek qarang

• Cross multiplication
• 0.999...
• Bir nechta
• FRACTRAN

Izohlar

Adabiyotlar

Tashqi havolalar

• "Fraction, arithmetical". The Online Encyclopaedia of Mathematics.
• "Fraction". Britannica entsiklopediyasi.
• "Fraction (mathematics)". Citizenium.
• "Fraction". PlanetMath. Arxivlandi asl nusxasidan 2019 yil 25 oktyabrda. Olingan 29 sentyabr 2019.