1.7: Ongeza na Ondoa sehemu
- Page ID
- 178075
Mwishoni mwa sehemu hii, utaweza:
- Ongeza au uondoe sehemu ndogo na denominator ya kawaida
- Ongeza au uondoe sehemu ndogo na madhehebu tofauti
- Tumia utaratibu wa shughuli ili kurahisisha sehemu ndogo
- Tathmini maneno ya kutofautiana na sehemu ndogo
Utangulizi wa kina zaidi wa mada yaliyofunikwa katika sehemu hii inaweza kupatikana katika sura ya Prealgebra, Sehemu ndogo.
Ongeza au Ondoa sehemu ndogo na Denominator ya kawaida
Wakati sisi kuzidisha sehemu, sisi tu kuzidisha numerators na kuzidisha denominators haki moja kwa moja hela. Ili kuongeza au kuondoa sehemu ndogo, lazima iwe na denominator ya kawaida.
Kama\(a,b\), na\(c\) ni idadi ambapo\(c\neq 0\), basi
\[\dfrac{a}{c} + \dfrac{b}{c} = \dfrac{a + b}{c} \quad \text{and} \quad \dfrac{a}{c} - \dfrac{b}{c} = \dfrac{a - b}{c}\]
Ili kuongeza au kuondoa sehemu ndogo, ongeza au uondoe nambari na uweke matokeo juu ya denominator ya kawaida.
Kufanya shughuli za Hisabati za Manipulative “Uongeze wa Fraction Model” na “Model Fraction Ondoa” itasaidia kuendeleza uelewa bora wa kuongeza na kuondoa sehemu ndogo.
Pata jumla:\(\dfrac{x}{3} + \dfrac{2}{3}\).
- Jibu
-
\[\begin{array} {ll} {} &{\dfrac{x}{3} + \dfrac{2}{3}} \\ {\text{Add the numerators and place the sum over the common denominator}} &{\dfrac{x + 2}{3}} \end{array}\]
Pata jumla:\(\dfrac{x}{4} + \dfrac{3}{4}\).
- Jibu
-
\(\dfrac{x + 3}{4}\)
Pata jumla:\(\dfrac{y}{8} + \dfrac{5}{8}\).
- Jibu
-
\(\dfrac{y + 5}{8}\)
Pata tofauti:\(-\dfrac{23}{24} - \dfrac{13}{24}\)
- Jibu
-
\[\begin{array} {ll} {} &{-\dfrac{23}{24} - \dfrac{13}{24}} \\ {\text{Subtract the numerators and place the }} &{\dfrac{-23 - 13}{24}} \\ {\text{difference over the common denominator}} &{} \\ {\text{Simplify.}} &{\dfrac{-36}{24}} \\ {\text{Simplify. Remember, }-\dfrac{a}{b} = \dfrac{-a}{b}} &{-\dfrac{3}{2}} \end{array}\]
Pata tofauti:\(-\dfrac{19}{28} - \dfrac{7}{28}\)
- Jibu
-
\(-\dfrac{26}{28}\)
Pata tofauti:\(-\dfrac{27}{32} - \dfrac{1}{32}\)
- Jibu
-
\(-\dfrac{7}{8}\)
Pata tofauti:\(-\dfrac{10}{x} - \dfrac{4}{x}\)
- Jibu
-
\[\begin{array} {ll} {} &{-\dfrac{10}{x} - \dfrac{4}{x}} \\ {\text{Subtract the numerators and place the }} &{\dfrac{-14}{x}} \\ {\text{difference over the common denominator}} &{} \\ {\text{Rewrite with the sign in front of the fraction.}} &{-\dfrac{14}{x}} \end{array}\]
Pata tofauti:\(-\dfrac{9}{x} - \dfrac{7}{x}\)
- Jibu
-
\(-\dfrac{16}{x}\)
Pata tofauti:\(-\dfrac{17}{a} - \dfrac{5}{a}\)
- Jibu
-
\(-\dfrac{22}{a}\)
Kurahisisha:\(\dfrac{3}{8} + (-\dfrac{5}{8}) - \dfrac{1}{8}\)
- Jibu
-
\[\begin{array} {ll} {\text{Add and Subtract fractions — do they have a }} &{\frac{3}{8} + (-\frac{5}{8}) - \frac{1}{8}} \\ {\text{common denominator? Yes.}} &{} \\ {\text{Add and subtract the numerators and place }} &{\frac{3 + (-5) - 1}{8}} \\ {\text{the result over the common denominator.}} &{} \\ {\text{Simplify left to right.}} &{\frac{-2 - 1}{8}} \\ {\text{Simplify.}} &{-\frac{3}{8}} \end{array}\]
Kurahisisha:\(\dfrac{2}{9} + (-\dfrac{4}{9}) - \dfrac{7}{9}\)
- Jibu
-
\(-1\)
Kurahisisha:\(\dfrac{2}{5} + (-\dfrac{4}{9}) - \dfrac{7}{9}\)
- Jibu
-
\(-\dfrac{2}{3}\)
Ongeza au Ondoa sehemu na Denominators tofauti
Kama tulivyoona, kuongeza au kuondoa sehemu ndogo, denominators yao lazima iwe sawa. Denominator ya kawaida (LCD) ya sehemu mbili ni idadi ndogo ambayo inaweza kutumika kama denominator ya kawaida ya sehemu ndogo. LCD ya sehemu mbili ni ndogo zaidi ya kawaida (LCM) ya denominators yao.
Denominator ya kawaida (LCD) ya sehemu mbili ni ndogo zaidi ya kawaida (LCM) ya denominators yao.
Kufanya shughuli za Hisabati za Manipulative “Kutafuta Denominator ya kawaida” itakusaidia kuendeleza uelewa bora wa LCD.
Baada ya kupata denominator ya kawaida ya sehemu mbili, tunabadilisha sehemu ndogo kwa sehemu sawa na LCD. Kuweka hatua hizi pamoja inatuwezesha kuongeza na kuondoa sehemu kwa sababu madhehebu yao yatakuwa sawa!
Ongeza:\(\dfrac{7}{12} + \dfrac{5}{18}\)
- Jibu
Ongeza:\(\dfrac{7}{12} + \dfrac{11}{15}\)
- Jibu
-
\(\dfrac{79}{60}\)
Ongeza:\(\dfrac{7}{12} + \dfrac{11}{15}\)
- Jibu
-
\(\dfrac{103}{60}\)
- Je, wana denominator ya kawaida?
- Ndiyo-nenda hatua ya 2.
- Hapana-Andika upya kila sehemu na LCD (denominator angalau ya kawaida). Kupata LCD. Badilisha kila sehemu katika sehemu sawa na LCD kama denominator yake.
- Ongeza au uondoe sehemu ndogo.
- Kurahisisha, ikiwa inawezekana.
Wakati wa kutafuta sehemu sawa zinazohitajika ili kuunda denominators ya kawaida, kuna njia ya haraka ya kupata nambari tunayohitaji kuzidisha nambari zote na denominator. Njia hii kazi kama sisi kupatikana LCD kwa factoring katika primes.
Angalia mambo ya LCD na kisha kila safu juu ya mambo hayo. Sababu za “kukosa” za kila denominator ni namba tunayohitaji.
Katika Zoezi\(\PageIndex{13}\), LCD, 36, ina mambo mawili ya 2 na mambo mawili ya 3.
Nambari 12 ina mambo mawili ya 2 lakini moja tu ya 3—hivyo ni “kukosa” moja 3—tunazidisha namba na denominator kwa 3.
Nambari 18 inakosa sababu moja ya 2—hivyo tunazidisha nambari na denominator kwa 2.
Tutatumia njia hii tunapoondoa sehemu ndogo katika Zoezi\(\PageIndex{16}\).
Ondoa:\(\dfrac{7}{15} - \dfrac{19}{24}\)
- Jibu
-
Je, sehemu ndogo zina denominator ya kawaida? Hapana, kwa hiyo tunahitaji kupata LCD.
Kupata LCD. Kumbuka, 15 ni “kukosa” mambo matatu ya 2 na 24 ni “kukosa” 5 kutokana na sababu za LCD. Kwa hiyo tunazidisha 8 katika sehemu ya kwanza na 5 katika sehemu ya pili ili kupata LCD. Andika upya kama sehemu ndogo sawa na LCD. Kurahisisha. Ondoa. \(-\dfrac{39}{120}\) Angalia ili uone kama jibu linaweza kuwa rahisi. \(-\dfrac{13\cdot3}{40\cdot3}\) Wote 39 na 120 wana sababu ya 3. Kurahisisha. \(-\dfrac{13}{40}\) Je, si kurahisisha sehemu sawa! Kama wewe, itabidi kupata nyuma sehemu ya awali na kupoteza denominator kawaida!
Ondoa:\(\dfrac{13}{24} - \dfrac{17}{32}\)
- Jibu
-
\(\dfrac{1}{96}\)
Ondoa:\(\dfrac{7}{15} - \dfrac{19}{24}\)
- Jibu
-
\(\dfrac{75}{224}\)
Katika mfano unaofuata, moja ya sehemu ndogo ina variable katika nambari yake. Kumbuka kwamba tunafanya hatua sawa na wakati nambari zote mbili ni namba.
Ongeza:\(\dfrac{3}{5} + \dfrac{x}{8}\)
- Jibu
-
Sehemu ndogo zina madhehebu tofauti.
Kupata LCD. Andika upya kama sehemu ndogo sawa na LCD. Kurahisisha. Ongeza. Kumbuka, tunaweza tu kuongeza kama maneno:\(24\) na\(5x\) si kama maneno.
Ongeza:\(\dfrac{y}{6} + \dfrac{7}{9}\)
- Jibu
-
\(\dfrac{3y + 14}{18}\)
Ongeza:\(\dfrac{x}{6} + \dfrac{7}{15}\)
- Jibu
-
\(\dfrac{15x + 42}{153}\)
Sasa tuna shughuli zote nne kwa sehemu ndogo. Jedwali\(\PageIndex{1}\) linafupisha shughuli za sehemu.
Kuzidisha sehemu | Sehemu ya Idara |
\(\dfrac{a}{b}\cdot \dfrac{c}{d} = \dfrac{ac}{bd}\) Kuzidisha nambari na kuzidisha denominators |
\(\dfrac{a}{b}\div \dfrac{c}{d} = \dfrac{a}{b} \cdot \dfrac{d}{c}\) Panua sehemu ya kwanza kwa usawa wa pili. |
Sehemu ya kuongeza | Fraction Ondoa |
\(\dfrac{a}{c} + \dfrac{b}{c} = \dfrac{a + b}{c}\) Ongeza nambari na uweke jumla juu ya denominator ya kawaida. |
\(\dfrac{a}{c} + \dfrac{b}{c} = \dfrac{a + b}{c}\) Ondoa nambari na uweke tofauti juu ya denominator ya kawaida. |
Ili kuzidisha au kugawanya sehemu ndogo, na LCD haihitajiki. Ili kuongeza au kuondoa sehemu ndogo, LCD inahitajika. |
Kurahisisha:
- \(\dfrac{5x}{6} - \dfrac{3}{10}\)
- \(\dfrac{5x}{6}\cdot \dfrac{3}{10}\).
- Jibu
-
Kwanza uulize, “Kazi ni nini?” Mara baada ya kutambua operesheni ambayo itaamua kama tunahitaji denominator ya kawaida. Kumbuka, tunahitaji denominator ya kawaida ili kuongeza au kuondoa, lakini si kuzidisha au kugawanya.
1. Operesheni ni nini? Uendeshaji ni kuondoa.
\[\begin{array} {ll} {\text{Do the fractions have a common denominator? No.}} &{\frac{5x}{6} - \frac{3}{10}} \\ {\text{Rewrite each fractions as an equivalent fraction with the LCD.}} &{\frac{5x\cdot 5}{6\cdot 5} - \frac{3\cdot3}{10\cdot3}} \\ {} &{\frac{25x}{30} - \frac{9}{30}} \\{\text{Subtract the numerators and place the difference over the}} &{\frac{25x - 9}{30}} \\ {\text{common denominators.}} &{} \\ {\text{Simplify, if possible. There are no common factors.}} &{} \\ {\text{The fraction is simplified.}} &{} \end{array}\]
2. Operesheni ni nini? Kuzidisha.
\[\begin{array} {ll} {} &{\frac{5x}{6}\cdot \frac{3}{10}} \\ {\text{To multiply fractions, multiply the numerators and multiply}} &{\frac{5x\cdot 3}{6\cdot 10}} \\ {\text{the denominators}} &{} \\{\text{Rewrite, showing common factors.}} &{\frac{\not 5 x\cdot\not3}{2\cdot\not3\cdot2\cdot\not5}} \\ {\text{common denominators.}} &{} \\ {\text{Simplify.}} &{\frac{x}{4}} \end{array}\]
Kurahisisha:
- \(\dfrac{3a}{4} - \dfrac{8}{9}\)
- \(\dfrac{3a}{4}\cdot\dfrac{8}{9}\)
- Jibu
-
- \(\dfrac{27a - 32}{36}\)
- \(\dfrac{2a}{3}\)
Kurahisisha:
- \(\dfrac{4k}{5} - \dfrac{1}{6}\)
- \(\dfrac{4k}{5}\cdot\dfrac{1}{6}\)
- Jibu
-
- \(\dfrac{24k - 5}{30}\)
- \(\dfrac{2k}{15}\)
Tumia Utaratibu wa Uendeshaji ili kurahisisha Fractions Complex
Tumeona kwamba sehemu tata ni sehemu ambayo nambari au denominator ina sehemu. Bar ya sehemu inaonyesha mgawanyiko. Sisi kilichorahisisha sehemu tata\(\dfrac{\frac{3}{4}}{\frac{5}{8}}\) kwa kugawa\(\dfrac{3}{4}\) na\(\dfrac{5}{8}\).
Sasa tutaangalia sehemu ndogo ambapo namba au denominator ina maneno ambayo yanaweza kuwa rahisi. Kwa hiyo sisi kwanza tunapaswa kurahisisha kabisa nambari na denominator tofauti kwa kutumia utaratibu wa shughuli. Kisha tunagawanya nambari na denominator.
Kurahisisha:\(\dfrac{(\frac{1}{2})^{2}}{4 + 3^{2}}\)
- Jibu
-
Kurahisisha:\(\dfrac{(\frac{1}{3})^{2}}{2^{3} + 2}\)
- Jibu
-
\(\dfrac{1}{90}\)
Kurahisisha:\(\dfrac{1 + 4^{2}}{(\frac{1}{4})^{2}}\)
- Jibu
-
\(272\)
- Kurahisisha nambari.
- Kurahisisha denominator.
- Gawanya nambari kwa denominator. Kurahisisha kama inawezekana.
Kurahisisha:\(\dfrac{\frac{1}{2} + \frac{2}{3}}{\frac{3}{4} - \frac{1}{6}}\)
- Jibu
-
\[\begin{array} {ll} {} &{\frac{(\frac{1}{2} + \frac{2}{3})}{(\frac{3}{4} - \frac{1}{6})}} \\ {\text{Simplify the numerator (LCD = 6) and simplify the denominator (LCD = 12).}} &{\frac{(\frac{3}{6} + \frac{4}{6})}{(\frac{9}{12} - \frac{2}{12})}} \\ {\text{Simplify.}} &{\frac{(\frac{7}{6})}{(\frac{7}{12})}} \\{\text{Divide the numerator by the denominator.}} &{\frac{7}{6}\div\frac{7}{12}} \\ {\text{Simplify.}} &{\frac{7}{6}\cdot\frac{12}{7}} \\ {\text{Divide out common factors.}} &{\frac{7\cdot6\cdot2}{6\cdot7}} \\ {\text{Simplify.}} &{2} \end{array}\]
Kurahisisha:\(\dfrac{\frac{1}{3} + \frac{1}{2}}{\frac{3}{4} - \frac{1}{3}}\)
- Jibu
-
\(2\)
Kurahisisha:\(\dfrac{\frac{2}{3} - \frac{1}{2}}{\frac{1}{4} + \frac{1}{3}}\)
- Jibu
-
\(\dfrac{2}{7}\)
Tathmini Maneno ya kutofautiana na FRACTIONS
Tumepima maneno kabla, lakini sasa tunaweza kutathmini maneno na sehemu ndogo. Kumbuka, kutathmini maneno, sisi badala ya thamani ya kutofautiana katika kujieleza na kisha kurahisisha.
Tathmini\(x + \dfrac{1}{3}\) wakati
- \(x = -\dfrac{1}{3}\)
- \(x = -\dfrac{3}{4}\)
- Jibu
-
1. Kutathmini\(x + \dfrac{1}{3}\) wakati\(x = -\dfrac{1}{3}\), badala\(-\dfrac{1}{3}\) ya\(x\) katika kujieleza.
Kurahisisha. \(0\)
2. Kutathmini\(x + \dfrac{1}{3}\) wakati\(x = -\dfrac{3}{4}\), badala\(-\dfrac{3}{4}\) ya\(x\) katika kujieleza.Andika upya kama sehemu ndogo sawa na LCD, 12. Kurahisisha. Ongeza. \(-\dfrac{5}{12}\)
Tathmini\(x + \dfrac{3}{4}\) wakati
- \(x = -\dfrac{7}{4}\)
- \(x = -\dfrac{5}{4}\)
- Jibu
-
- \(-1\)
- \(-\dfrac{1}{2}\)
Tathmini\(y + \dfrac{1}{2}\) wakati
- \(y = \dfrac{2}{3}\)
- \(y = -\dfrac{3}{4}\)
- Jibu
-
- \(\dfrac{7}{6}\)
- \(-\dfrac{1}{12}\)
Tathmini\(-\dfrac{5}{6} - y\) wakati\(y = -\dfrac{2}{3}\)
- Jibu
-
Andika upya kama sehemu ndogo sawa na LCD,\(6\). Ondoa. Kurahisisha. \(-\dfrac{1}{6}\)
Tathmini\(y + \dfrac{1}{2}\) wakati\(y = \dfrac{2}{3}\)
- Jibu
-
\(-\dfrac{1}{4}\)
Tathmini\(y + \dfrac{1}{2}\) wakati\(y = \dfrac{2}{3}\)
- Jibu
-
\(-\dfrac{17}{8}\)
Tathmini\(2x^{2}y\)\(x = \dfrac{1}{4}\) lini na\(y = -\dfrac{2}{3}\).
- Jibu
-
Badilisha maadili katika maneno.
\(2x^{2}y\) Kurahisisha watetezi kwanza. \(2(\frac{1}{16})(-\frac{2}{3})\) Kuzidisha. Gawanya mambo ya kawaida. Angalia tunaandika\(16\) kama\(2\cdot2\cdot4\) ili iwe rahisi kuondoa \(-\frac{\not2\cdot1\cdot\not2}{\not2\cdot\not2\cdot4\cdot3}\) Kurahisisha. \(-\frac{1}{12}\)
Tathmini\(3ab^{2}\)\(a = -\dfrac{2}{3}\) lini na\(b = -\dfrac{1}{2}\).
- Jibu
-
\(-\dfrac{1}{2}\)
Tathmini\(4c^{3}d\)\(c = -\dfrac{1}{2}\) lini na\(d = -\dfrac{4}{3}\).
- Jibu
-
\(\dfrac{2}{3}\)
Mfano unaofuata utakuwa na vigezo tu, hakuna mara kwa mara.
Tathmini\(\dfrac{p + q}{r}\) wakati\(p = -4, q = -2\), na\(r = 8\).
- Jibu
-
Kutathmini\(\dfrac{p + q}{r}\) wakati\(p = -4, q = -2\), na\(r = 8\), sisi badala ya maadili katika kujieleza.
\(\dfrac{p + q}{r}\) Ongeza kwenye nambari ya kwanza. \(\dfrac{-6}{8}\) Kurahisisha. \(-\dfrac{3}{4}\)
Tathmini\(\dfrac{a+b}{c}\) wakati\(a = -8, b = -7\), na\(c = 6\).
- Jibu
-
\(-\dfrac{5}{2}\)
Tathmini\(\dfrac{x+y}{z}\) wakati\(x = 9, y = -18\), na\(z = -6\).
- Jibu
-
\(\dfrac{3}{2}\)
Dhana muhimu
- Sehemu Aidha na Ondoa: Kama\(a, b\), na\(c\) ni idadi ambapo\(c\neq 0\), kisha
\(\dfrac{a}{c} + \dfrac{b}{c} = \dfrac{a+b}{c}\) na\(\dfrac{a}{c} - \dfrac{b}{c} = \dfrac{a-b}{c}\)
Kuongeza au Ondoa sehemu, kuongeza au Ondoa nambari na mahali matokeo juu ya denominator ya kawaida.
- Mkakati wa Kuongeza au Kuondoa FRACTIONS
- Je, wana denominator ya kawaida?
Ndiyo-nenda hatua ya 2.
Hapana—Andika upya kila sehemu na LCD (Denominator isiyo ya kawaida). Kupata LCD. Badilisha kila sehemu katika sehemu sawa na LCD kama denominator yake. - Ongeza au uondoe sehemu ndogo.
- Kurahisisha, ikiwa inawezekana. Ili kuzidisha au kugawanya sehemu ndogo, LCD haihitajiki. Ili kuongeza au kuondoa sehemu ndogo, LCD inahitajika.
- Je, wana denominator ya kawaida?
- Kurahisisha Fractions Complex
- Kurahisisha nambari.
- Kurahisisha denominator.
- Gawanya nambari kwa denominator. Kurahisisha kama inawezekana.