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\(\dfrac{2}{9}\times\dfrac{3}{5}+\dfrac{6}{11}+\dfrac{13}{9}\times\dfrac{3}{5}+\dfrac{5}{11}\)

\(=\dfrac{3}{5}\times\left(\dfrac{2}{9}+\dfrac{13}{9}\right)+1\)

\(=\dfrac{3}{5}\times\dfrac{15}{9}+1=1+1=2\)

a) \(1678\cdot24+77\cdot1678-1678=1678\left(24+77-1\right)=167800\)

b) Ta có: \(\dfrac{2}{5}+\dfrac{4}{11}+\dfrac{3}{5}+\dfrac{18}{11}+\dfrac{1}{4}+\dfrac{1}{6}\)

\(=\left(\dfrac{2}{5}+\dfrac{3}{5}\right)+\left(\dfrac{4}{11}+\dfrac{18}{11}\right)+\dfrac{1}{4}+\dfrac{1}{6}\)

\(=3+\dfrac{1}{4}+\dfrac{1}{6}\)

\(=\dfrac{36}{12}+\dfrac{3}{12}+\dfrac{2}{12}=\dfrac{41}{12}\)

5 tháng 5 2016

a, 3/5 x 7/9 + 11/9 x 3/5 = 3/5 x (7/9 + 11/9) = 3/5 x 2 = 6/5

b, 14/13 : 1/2 + 3/13 x 2 - 2 x 7/13

= 14/13 x 2 + 3/13 x 2 - 2 x 7/13

= 2 x ( 14/13 + 3/13 - 7/13)

= 2 x 10/13 = 20/13

a: \(=\dfrac{3}{5}+\dfrac{2}{7}=\dfrac{21+10}{35}=\dfrac{31}{35}\)

b: \(=\dfrac{6}{5}+\dfrac{3}{2}\cdot\dfrac{1}{3}=\dfrac{6}{5}+\dfrac{1}{2}=\dfrac{12+5}{10}=\dfrac{17}{10}\)

c: \(=\dfrac{5\cdot3}{9}=\dfrac{5}{3}\)

d: =5-2/3*6/5

=5-12/15

=5-4/5

=21/5

10 tháng 5 2017

a)2/5+3/10-1/2=7/10-1/2=2/10=1/5

b)8/11+8/33x3/4=8/11+2/11=10/11

c)7/9x3/14:5/8=1/6:5/8=8/30+4/15

d)5/12-7/32:21/16=5/12-1/6=3/12

nha

10 tháng 5 2017

a) 2/5+3/10-1/2

= 4/10+3/10-5/10

= 2/10 = 1/5

b) 8/11+8/33x3/4

= 8/11+2/11

= 10/11

c) 7/9x3/14:5/8

= 1/6:5/8

= 1/6x8/5

=4/15

d) 5/12-7/32:21/16

= 5/12-7/32x16/21

= 5/12-1/6

= 5/12-2/12

= 3/12

Trl:

3 x 9 + 6 x 3 + 5 : 2 - 6 + 9 x 3 - 2

= 27 + 18 + 2,5 - 6 + 27 - 2

= 66,5

#HuyềnAnh#

15 tháng 12 2019

Trl :

    3 x 9 + 6 x 3 + 5 : 2 - 6 + 9 x 3 - 2

= 27 + 18 + 2,5 -  6 + 27 - 2

= 45 + 2,5 - 6 + 27 - 2 

= 66,5

_ Jie _

17 tháng 5 2020

\(\frac{7}{9}\times\frac{3}{5}+\frac{3}{5}\times\frac{5}{6}+\frac{3}{5}\times1\)

\(=\frac{3}{5}\times\left(\frac{7}{9}+\frac{5}{6}+1\right)\)

\(=\frac{3}{5}\times\frac{47}{18}\)

\(=\frac{47}{30}\)

 #hoktot<3# 

15 tháng 2 2017

\(\frac{5}{9}x\frac{4}{7}+\frac{5}{9}x\frac{3}{7}\)

\(=\frac{5}{9}x\left(\frac{4}{7}+\frac{3}{7}\right)\)

\(=\frac{5}{9}x1\)

\(=\frac{5}{9}\)

15 tháng 2 2017

\(\frac{5}{9}\) x \(\frac{4}{7}\)\(\frac{5}{9}\)\(\frac{3}{7}\)

\(\frac{5}{9}\)x ( \(\frac{4}{7}\)\(\frac{3}{7}\))

\(\frac{5}{9}\) x 1 

\(\frac{5}{9}\)

17 tháng 2 2022

5/9 x 3/8 =

C1: 5/9 x 3/8 = 15/72 = 5/24

C2: 5/9 x 3/8 = 5/3 x 8 = 5/24

k vs ạ

17 tháng 2 2022

5/9 x 3/8 = 5/24 nhé!

\(\dfrac{19}{20}-y=\dfrac{8}{5}-\dfrac{3}{4}\)

\(\Leftrightarrow\dfrac{19}{20}-y=\dfrac{32-15}{20}\)

\(\Leftrightarrow\dfrac{19}{20}-y=\dfrac{17}{20}\Leftrightarrow y=\dfrac{19}{20}-\dfrac{17}{20}=\dfrac{2}{20}=\dfrac{1}{10}\)

\(y:\dfrac{2}{3}=\dfrac{4}{9}.3\)

\(\Leftrightarrow y:\dfrac{2}{3}=\dfrac{12}{9}\Leftrightarrow y=\dfrac{12}{9}.\dfrac{2}{3}=\dfrac{8}{9}\)

\(a.\dfrac{19}{20}-y=\dfrac{17}{20}\)

\(y=\dfrac{2}{17}\)

\(b.y:\dfrac{2}{3}=\dfrac{4}{3}\)

\(y=\dfrac{8}{9}\)