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\(\dfrac{5}{16}+\dfrac{12}{8}+\dfrac{2}{3}=\dfrac{5.3}{16.3}+\dfrac{12.6}{8.6}+\dfrac{2.16}{3.16}=\dfrac{15}{48}+\dfrac{72}{48}+\dfrac{32}{48}=\dfrac{15+72+32}{48}=\dfrac{119}{48}\)

Chú ý : dấu . là dấu nhân nhé 

17 tháng 4 2022

a) \(2:\dfrac{2}{7}+\dfrac{12}{5}=\dfrac{2}{1}:\dfrac{2}{7}+\dfrac{12}{5}=7+\dfrac{12}{5}=\dfrac{47}{5}\)

b) \(\dfrac{5}{16}:\left(\dfrac{5}{8}+\dfrac{3}{24}\right)=\dfrac{5}{16}:\dfrac{3}{4}=\dfrac{5}{16}\times\dfrac{4}{3}=\dfrac{20}{48}=\dfrac{5}{12}\)

29 tháng 10 2023

\(\dfrac{1}{3}+\dfrac{2}{9}=\dfrac{3}{3\times3}+\dfrac{2}{9}=\dfrac{3}{9}+\dfrac{2}{9}=\dfrac{5}{9}\)

\(\dfrac{1}{2}+\dfrac{3}{8}=\dfrac{4}{2\times4}+\dfrac{3}{8}=\dfrac{4}{8}+\dfrac{3}{8}=\dfrac{7}{8}\)

\(\dfrac{5}{12}+\dfrac{2}{3}=\dfrac{5}{12}+\dfrac{2\times4}{3\times4}=\dfrac{5}{12}+\dfrac{8}{12}=\dfrac{13}{12}\)

\(\dfrac{5}{16}+\dfrac{3}{8}=\dfrac{5}{16}+\dfrac{3\times2}{8\times2}=\dfrac{5}{16}+\dfrac{6}{16}=\dfrac{11}{16}\)

\(\dfrac{4}{15}+\dfrac{3}{5}=\dfrac{4}{15}+\dfrac{3\times3}{5\times3}=\dfrac{4}{15}+\dfrac{9}{15}=\dfrac{13}{15}\)

\(\dfrac{8}{63}+\dfrac{7}{10}=\dfrac{8\times10}{63\times10}+\dfrac{7\times63}{10\times63}=\dfrac{80}{630}+\dfrac{441}{630}=\dfrac{521}{630}\)

10 tháng 10 2015

Bài 1:

\(\frac{1}{12},\frac{2}{3},\frac{3}{4},\frac{5}{6}\)

Bài 2:

A. \(\frac{11}{6}\)

B. \(\frac{3}{32}\)

C. \(\frac{1}{7}\)

D. \(\frac{15}{8}\)

Tích đúng cho mình nhé!

15 tháng 4 2022

a)\(=\dfrac{16}{13}-\dfrac{3}{15}+\dfrac{6}{13}=\dfrac{22}{13}-\dfrac{3}{15}=\dfrac{96}{65}\)

b)\(=\dfrac{21}{8}-\left(\dfrac{5}{10}+\dfrac{6}{10}\right)=\dfrac{21}{8}-\dfrac{11}{10}=\dfrac{61}{40}\)

c)\(=\dfrac{27}{10}-3-\dfrac{4}{7}--\dfrac{61}{70}\)

15 tháng 4 2022

d)\(=\dfrac{576}{702}=\dfrac{4}{5}\)

e)\(=\left(\dfrac{20}{15}-\dfrac{12}{15}\right)\times\dfrac{25}{2}=\dfrac{8}{15}\times\dfrac{25}{2}=\dfrac{20}{3}\)

f)\(=\dfrac{24}{12}-\dfrac{4}{12}-\dfrac{6}{12}-\dfrac{2}{12}-\dfrac{3}{12}=\dfrac{9}{12}=\dfrac{3}{4}\)

7 tháng 2 2018

1)     \(\frac{1}{12}+\frac{1}{16}+\frac{3}{4}\)

\(=\frac{4}{48}+\frac{3}{48}+\frac{36}{48}\)

\(=\frac{4+3+36}{48}\)

\(=\frac{43}{48}\)

2)   a)    \(\frac{1}{15}+\frac{4}{15}+\frac{5}{18}+\frac{7}{18}\)

\(=\left(\frac{1}{15}+\frac{4}{15}\right)+\left(\frac{5}{18}+\frac{7}{18}\right)\)

\(=\frac{1}{3}+\frac{2}{3}=1\)

b)    \(\frac{1}{8}+\frac{1}{12}+\frac{3}{8}+\frac{5}{12}\)

\(=\left(\frac{1}{8}+\frac{3}{8}\right)+\left(\frac{1}{12}+\frac{5}{12}\right)\)

\(=\frac{1}{2}+\frac{1}{2}=1\)

7 tháng 4 2020

Bài 1: Tính

\(a.\frac{15}{16}-\frac{7}{16}=\frac{15-7}{16}=\frac{8}{16}=\frac{1}{2}\)

\(b.\frac{7}{4}-\frac{3}{4}=\frac{7-3}{4}=\frac{4}{4}=1\)

\(c.\frac{9}{5}-\frac{3}{5}=\frac{9-3}{5}=\frac{6}{5}\)

\(d.\frac{17}{49}-\frac{12}{49}=\frac{17-12}{49}=\frac{5}{49}\)

Bài 2:Rút gọn rồi tính

\(a.\frac{2}{3}-\frac{3}{9}=\frac{2}{3}-\frac{1}{3}=\frac{2-1}{3}=\frac{1}{3}\)

\(b.\frac{7}{5}-\frac{15}{25}=\frac{7}{5}-\frac{3}{5}=\frac{7-3}{5}=\frac{4}{5}\)

Học tốt. K cho mik nha

7 tháng 4 2020

Trl :

Bạn kia làm đúng rồi nhé !

Học tốt nhé bạn @

26 tháng 4 2017

3 ×17 + 3 × 25 - 3 × 2 = 3 × (17 + 25 – 2) = 3 × 40 = 120

6 tháng 11

3x(17+25-2)=3x40=120

 

29 tháng 10 2023

\(\dfrac{1}{2}-\dfrac{3}{8}=\dfrac{4}{2\times4}-\dfrac{3}{8}=\dfrac{4}{8}-\dfrac{3}{8}=\dfrac{1}{8}\)

\(\dfrac{4}{3}-\dfrac{8}{15}=\dfrac{4\times5}{3\times5}-\dfrac{8}{15}=\dfrac{20}{15}-\dfrac{8}{15}=\dfrac{12}{15}=\dfrac{4}{5}\)

\(\dfrac{5}{6}-\dfrac{7}{12}=\dfrac{5\times2}{6\times2}-\dfrac{7}{12}=\dfrac{10}{12}-\dfrac{7}{12}=\dfrac{3}{12}=\dfrac{1}{4}\)

\(\dfrac{11}{4}-\dfrac{9}{8}=\dfrac{11\times2}{4\times2}-\dfrac{9}{8}=\dfrac{22}{8}-\dfrac{9}{8}=\dfrac{13}{8}\)

\(\dfrac{17}{16}-\dfrac{3}{4}=\dfrac{17}{16}-\dfrac{3\times4}{4\times4}=\dfrac{17}{16}-\dfrac{12}{16}=\dfrac{5}{16}\)

\(\dfrac{31}{36}-\dfrac{5}{6}=\dfrac{31}{36}-\dfrac{5\times6}{6\times6}=\dfrac{31}{36}-\dfrac{30}{36}=\dfrac{1}{36}\)

a: =24/15-18/15=6/15=2/5

b: =78/42-24/42=54/42=9/7

c: =30/36-12/36=18/36=1/2

d: =7/8-1/8-3/34=6/8-3/34=3/4-3/34=45/68