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23 tháng 1 2020

                                                                Bài giải

a, \(\frac{4}{5}-\frac{2}{3}+\frac{1}{5}-\frac{1}{3}\)

\(=\left(\frac{4}{5}+\frac{1}{5}\right)-\left(\frac{2}{3}+\frac{1}{3}\right)=1-1=0\)

b, \(\frac{2}{5}\text{ x }\frac{7}{4}-\frac{2}{5}\text{ x }\frac{3}{7}\)

\(=\frac{2}{5}\text{ x }\left(\frac{7}{4}-\frac{3}{7}\right)=\frac{2}{5}\text{ x }\frac{37}{28}=\frac{37}{70}\)

c, \(\frac{13}{4}\text{ x }\frac{2}{3}\text{ x }\frac{4}{13}\text{ x }\frac{3}{12}=\frac{13\text{ x }2\text{ x }4\text{ x }3}{4\text{ x }3\text{ x }13\text{ x }12}=\frac{1}{6}\)

d,  \(\frac{75}{100}+\frac{18}{21}+\frac{19}{32}+\frac{1}{4}+\frac{3}{21}+\frac{13}{32}\)

\(=\frac{3}{4}+\frac{18}{21}+\frac{19}{32}+\frac{1}{4}+\frac{3}{21}+\frac{13}{32}\)

\(=\left(\frac{3}{4}+\frac{1}{4}\right)+\left(\frac{18}{21}+\frac{3}{21}\right)+\left(\frac{19}{32}+\frac{13}{32}\right)\)

\(=1+1+1\)

\(=3\)

e, \(\frac{2}{5}+\frac{6}{9}+\frac{3}{4}+\frac{3}{5}+\frac{1}{3}+\frac{1}{4}\)

\(=\frac{2}{5}+\frac{2}{3}+\frac{3}{4}+\frac{3}{5}+\frac{1}{3}+\frac{1}{4}\)

\(=\frac{1}{5}\left(2+3\right)+\frac{1}{3}\left(2+1\right)+\frac{1}{4}\left(3+1\right)\)

\(=\frac{1}{5}\cdot5+\frac{1}{3}\cdot3+\frac{1}{4}\cdot4\)

\(=1+1+1\)

\(=3\)

23 tháng 1 2020

a, \(\frac{4}{5}-\frac{2}{3}+\frac{1}{5}-\frac{1}{3}\)

\(=\left(\frac{4}{5}+\frac{1}{5}\right)-\left(\frac{2}{3}+\frac{1}{3}\right)=1-1=0\)

b, \(\frac{2}{5}\text{ x }\frac{7}{4}-\frac{2}{5}\text{ x }\frac{3}{7}\)

\(=\frac{2}{5}\text{ x }\left(\frac{7}{4}-\frac{3}{7}\right)=\frac{2}{5}\text{ x }\frac{37}{28}=\frac{37}{70}\)

c, \(\frac{13}{4}\text{ x }\frac{2}{3}\text{ x }\frac{4}{13}\text{ x }\frac{3}{12}=\frac{13\text{ x }2\text{ x }4\text{ x }3}{4\text{ x }3\text{ x }13\text{ x }12}=\frac{1}{6}\)

d,  \(\frac{75}{100}+\frac{18}{21}+\frac{19}{32}+\frac{1}{4}+\frac{3}{21}+\frac{13}{32}\)

\(=\frac{3}{4}+\frac{18}{21}+\frac{19}{32}+\frac{1}{4}+\frac{3}{21}+\frac{13}{32}\)

\(=\left(\frac{3}{4}+\frac{1}{4}\right)+\left(\frac{18}{21}+\frac{3}{21}\right)+\left(\frac{19}{32}+\frac{13}{32}\right)\)

\(=1+1+1\)

\(=3\)

e, \(\frac{2}{5}+\frac{6}{9}+\frac{3}{4}+\frac{3}{5}+\frac{1}{3}+\frac{1}{4}\)

\(=\frac{2}{5}+\frac{2}{3}+\frac{3}{4}+\frac{3}{5}+\frac{1}{3}+\frac{1}{4}\)

\(=\frac{1}{5}\left(2+3\right)+\frac{1}{3}\left(2+1\right)+\frac{1}{4}\left(3+1\right)\)

\(=\frac{1}{5}\cdot5+\frac{1}{3}\cdot3+\frac{1}{4}\cdot4\)

\(=1+1+1\)

\(=3\)

4 tháng 4 2022

a. 1/240 : 43/60 = 1/172

b. 59/60 x 22/15 = 649/450

4 tháng 4 2022

1/172

649/450

15 tháng 2 2018

\(5-\frac{13}{17}=\frac{5}{1}-\frac{13}{17}=\frac{85}{17}-\frac{13}{17}=\frac{72}{17}\)

\(\frac{2}{5}-\frac{1}{7}=\frac{14}{35}-\frac{5}{35}=\frac{9}{35}\)

\(\frac{4}{9}-\frac{2}{9}=\frac{4-2}{9}=\frac{2}{9}\)

\(\frac{5}{4}-\frac{1}{3}=\frac{15}{12}-\frac{4}{12}=\frac{11}{12}\)

\(\frac{5}{2}-\frac{1}{4}-\frac{2}{3}=\frac{30}{12}-\frac{3}{12}-\frac{8}{12}=\frac{19}{12}\)

\(\frac{4}{3}-\frac{2}{5}+\frac{1}{2}=\frac{40}{30}-\frac{12}{30}+\frac{15}{30}=\frac{40-12+15}{30}=\frac{53}{30}\)

tk cho mk,mk đang bị trừ điểm

2 tháng 5 2016

Bài 1

1/2 x 3/4 : 4/5 

= 3/8 : 4/5 

= 3/8 x 5/4

= 15/32

2/3 + 1/6 - 1/2

= 4/6 + 1/6 - 3/6

= 5/6 - 3/6

= 1/3

3/5 + 4 : 2/3 - 3/2

= 3/5 + 4 x 3/2 - 3/2

= 3/5 + 6 - 3/2

= 3/5 + 30/5 - 3/2

= 33/5 - 3/2

= 66/10 - 15/10

= 28/5

Bài 2

x - 1/4 = 1/2 

x         = 1/2 + 1/4

x         = 2/4 + 1/4 

x         = 3/4

2/3 + x = 1

         x = 1 - 2/3 

         x = 3/3 - 2/3

         x = 1/3

2 tháng 5 2016

1/2 x 3/4 : 4/5

=1/2 x 3/4 x 4/5

=3/8 x 4/5

=3/10

21 tháng 11 2024

   \(\dfrac{2}{5}+\dfrac{2}{3}+\dfrac{2}{4}\)

\(\dfrac{24}{60}\) + \(\dfrac{40}{60}\) + \(\dfrac{30}{60}\)

\(\dfrac{64}{60}\) + \(\dfrac{30}{60}\)

\(\dfrac{47}{30}\)

\(\dfrac{2}{6}+\dfrac{3}{12}\)

\(\dfrac{4}{12}\) + \(\dfrac{3}{12}\)

\(\dfrac{7}{12}\)

\(\dfrac{5}{6}\) + \(\dfrac{1}{3}\)

\(\dfrac{5}{6}\) + \(\dfrac{2}{6}\)

\(\dfrac{7}{6}\)

 

 

21 tháng 11 2024

   \(\dfrac{1}{3}\) + \(\dfrac{5}{12}\) + \(\dfrac{5}{6}\)

\(\dfrac{4}{12}\) + \(\dfrac{5}{12}\) + \(\dfrac{10}{12}\)

\(\dfrac{9}{12}\) + \(\dfrac{10}{12}\)

\(\dfrac{19}{12}\)

    \(\dfrac{5}{8}\) + \(\dfrac{4}{7}\)

\(\dfrac{35}{56}\) + \(\dfrac{32}{56}\)

=  \(\dfrac{67}{56}\) 

\(\dfrac{7}{3}\) + \(\dfrac{8}{7}\)

\(\dfrac{49}{21}\) + \(\dfrac{24}{21}\)

\(\dfrac{73}{21}\)

   \(\dfrac{1}{5}+\dfrac{5}{35}\)

\(\dfrac{7}{35}\) + \(\dfrac{5}{35}\)

\(\dfrac{12}{35}\) 

14 tháng 4 2017

Gửi kết bn với mh nhé!

14 tháng 4 2017

ban ko tra loi ho minh cau nay a 

neu the minh ket ban kieu gi

3/5 + 4/5 * 2/5 = 3/5 + 8/25 = 15/25 + 8/25 = 23/25

9/16 * 4/3 + 1/2 : 3/4 = 3/4 + 2/3 = 9/12 + 8/12 = 17/12 

1/2 * 1/4 * 1/6 = 1/8 * 1/6 =1/48

1/4 : 1/3 - 4/2 = 1/4 : 1/3 - 2 = 3/4 -2 = 3/4 - 4/4 = -1/4