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9 tháng 3 2019
1/9+8/3-2/5=25/9-2/5=107/45
9 tháng 3 2019

Bằng một số

14 tháng 10 2023

\(5\dfrac{9}{10}:\dfrac{3}{2}-\left(2\dfrac{1}{3}\times4\dfrac{1}{2}-2\times2\dfrac{1}{3}\right):\dfrac{7}{4}\)

\(=\dfrac{59}{10}:\dfrac{3}{2}-\left(\dfrac{7}{3}\times\dfrac{9}{2}-2\times\dfrac{7}{3}\right):\dfrac{7}{4}\)

\(=\dfrac{59}{10}\cdot\dfrac{2}{3}-\left[\dfrac{7}{3}\times\left(\dfrac{9}{2}-2\right)\right]:\dfrac{7}{4}\)

\(=\dfrac{59}{15}-\left(\dfrac{7}{3}\times\dfrac{5}{2}\right):\dfrac{7}{4}\)

\(=\dfrac{59}{15}-\dfrac{35}{6}\cdot\dfrac{4}{7}\)

\(=\dfrac{59}{15}-\dfrac{10}{3}\)

\(=\dfrac{59}{15}-\dfrac{50}{15}\)

\(=\dfrac{9}{15}\)

\(=\dfrac{3}{5}\)

\(Toru\)

14 tháng 10 2023

ok

 

10 tháng 6 2015

1> a) \(\frac{5}{7}x4:\frac{5}{9}=\frac{5}{7}:\frac{5}{9}x4=\frac{5}{7}x\frac{9}{5}x4=\frac{9}{7}x4=\frac{9x4}{7}=\frac{36}{7}\)

\(b,8x\frac{2}{3}:\frac{1}{2}=8x\frac{2}{3}x\frac{2}{1}=8x2x\frac{2}{3}=16x\frac{2}{3}=\frac{32}{3}\)

\(c,6:\frac{3}{5}-\frac{7}{6}x\frac{6}{7}=6x\frac{5}{3}-1=10-1=9\)

\(\frac{21}{5}x\frac{10}{11}+\frac{57}{11}=\frac{42}{11}+\frac{57}{11}=\frac{99}{11}=9\)

2) a) \(\frac{35}{9}:x=\frac{35}{6}\)

\(x=\frac{35}{9}:\frac{35}{6}\)

\(x=\frac{35}{9}x\frac{6}{35}\)

\(x=\frac{2}{3}\)

b) \(\left(\frac{1}{1x2}+\frac{1}{2x3}+\frac{1}{3x4}+\frac{1}{4x5}+\frac{1}{5x6}\right)x10-X=0\)

\(\left(\frac{1}{1}-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+.....+\frac{1}{5}-\frac{1}{6}\right)x10-X=0\)

\(\left(\frac{1}{1}-\frac{1}{6}\right)x10-X=10\)

\(\frac{5}{6}x10-X=0\)

\(X=\frac{5}{6}x10=\frac{25}{3}\)

Đúng nha !!!!

10 tháng 6 2015

1/a/\(\frac{5}{7}\cdot4:\frac{5}{9}=\frac{20}{7}:\frac{5}{9}=\frac{20}{7}\cdot\frac{9}{5}=\frac{36}{7}\)

b/\(8\cdot\frac{2}{3}:\frac{1}{2}=\frac{16}{3}:\frac{1}{2}=\frac{16}{3}\cdot\frac{2}{1}=\frac{32}{3}\)

c/\(6:\frac{3}{5}-\frac{7}{6}\cdot\frac{6}{7}=6\cdot\frac{5}{3}-1=10-1=9\)

2/a/\(\frac{35}{9}:x=\frac{35}{6}\)

\(x=\frac{35}{9}:\frac{35}{6}=\frac{35}{9}\cdot\frac{6}{35}\)

\(x=\frac{2}{3}\)

 

b/\(\left(\frac{1}{1\cdot2}+\frac{1}{2\cdot3}+\frac{1}{3\cdot4}+\frac{1}{4\cdot5}+\frac{1}{5\cdot6}\right)\cdot10-x=0\)

\(\left(\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+\frac{1}{30}\right)\cdot10-x=0\)

\(\left(\frac{30}{60}+\frac{10}{60}+\frac{5}{60}+\frac{2}{30}\right)\cdot10-x=0\)

\(\frac{47}{60}\cdot10-x=0\)

\(\frac{47}{6}-x=0\)

\(x=\frac{47}{6}-0\)

\(x=\frac{47}{6}\)

21 tháng 7 2021

a)\(\frac{4}{5}-\frac{1}{4}+\frac{3}{10}\)

\(=\frac{16}{20}-\frac{5}{20}+\frac{6}{20}\)

\(=\frac{17}{20}\)

b) \(\frac{2}{5}:\left(1-\frac{1}{10}\right)\)

\(=\frac{2}{5}:\frac{9}{10}\)

\(=\frac{4}{9}\)

c)\(\frac{7}{8}\times\frac{4}{9}+\frac{1}{14}:\frac{5}{14}\)

\(=\frac{7}{18}+\frac{1}{5}\)

\(=\frac{53}{90}\)

d)\(\frac{2}{7}\times\frac{3}{11}+\frac{2}{7}\times\frac{8}{11}\)

\(=\frac{2}{7}\times\left(\frac{3}{11}+\frac{8}{11}\right)\)

\(=\frac{2}{7}\times1=\frac{2}{7}\)

e) \(12+\left(16-11\right)\times4\)

\(=12+20=32\)

f)\(2\frac{3}{7}+1\frac{4}{7}\)

\(=\frac{17}{7}+\frac{11}{7}\)

\(=4\)

g)\(\frac{2}{3}\times\frac{4}{5}+\frac{1}{5}:\frac{9}{11}\)

\(=\frac{8}{15}+\frac{11}{45}\)

\(=\frac{7}{9}\)

h)\(\left(6,2:2+3,7\right):0,2\)

\(=\left(3,1+3,7\right):0,2\)

\(=6,8:0,2=34\)

#H

4 tháng 8 2017

help meeeeeeeeeeeeeee

4 tháng 8 2017

mk chua gap dang nay bao gio

19 tháng 8 2020

TÍNH BẰNG CÁCH NHANH NHẤT NHA CÁC BN 

19 tháng 8 2020

a) \(\left(\frac{1}{3}+\frac{1}{5}\right)+\left(\frac{1}{6}-\frac{1}{5}\right)=\left(\frac{1}{3}+\frac{1}{6}\right)+\left(\frac{1}{5}-\frac{1}{5}\right)=\frac{1}{2}\)

b) \(\frac{3}{16}\times\frac{7}{5}+\frac{3}{5}\times\frac{9}{16}=\frac{21}{80}+\frac{27}{80}=\frac{48}{80}=\frac{3}{5}\)

c) \(\frac{1}{1\times2}+\frac{1}{2\times3}+...+\frac{1}{2020\times2021}=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+...+\frac{1}{2020}-\frac{1}{2021}\)

\(=1-\frac{1}{2021}=\frac{2020}{2021}\)

d) \(\frac{1}{1\times3}+\frac{1}{3\times5}+...+\frac{1}{2021\times2023}=\frac{1}{2}\times\left(\frac{2}{1\times3}+\frac{2}{3\times5}+...+\frac{2}{2021\times2023}\right)\)

\(=\frac{1}{2}\times\left(1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+...+\frac{1}{2021}-\frac{1}{2023}\right)\)

\(=\frac{1}{2}\times\left(1-\frac{1}{2023}\right)=\frac{1}{2}\times\frac{2022}{2023}=\frac{1011}{2023}\)

e) \(\frac{3}{2}\times\frac{1}{7}\times\frac{5}{4}+\frac{15}{2}\times\frac{6}{7}\times\frac{1}{4}==\frac{15}{56}+\frac{80}{56}=\frac{95}{56}\)

6 tháng 11 2016

\(\frac{2}{3}\times\frac{4}{5}-\frac{1}{3}\times\frac{4}{5}\)

\(=\frac{8}{15}-\frac{4}{15}\)

\(=\frac{4}{15}\)

k mk nha mấy bạn

6 tháng 11 2016

= 4/5 x (2/3 - 1/3 )

= 4/5 x 1/3

= 4/15