\(\left(\dfrac{2}{7}+\dfrac{5}{7}\right)+\left(\dfrac{3}{5}+\dfrac{2}{5}\right)+\left(\dfrac{3}{8}+\dfrac{4}{8}+\dfrac{1}{8}\right)+\left(\dfrac{1}{9}+\dfrac{8}{9}\right)=1+1+1+1=4\)

(2/7 + 5/7) + (3/5 + 2/5) + (3/8 + 4/8 + 1/8) + (1/9 + 8/9 )

= 1  +       1                   +         1             +        1         =  4

  13/8:5/6:3/5-2/3                      

=13/8x6/5x5/3-2/3

=13/8x[6/5x5/3]-2/3

=13/8x2-2/3

=13/4-2/3

=39/12-8/12

=31/12

= 3/7 nha

tính ra cách đi bạn

(13/17-5/17):8/3

=8/17:8/3

=3/17

=\(\dfrac{13}{17}:\dfrac{8}{3}-\dfrac{5}{17}:\dfrac{8}{3}\)

=\(\left(\dfrac{13}{17}-\dfrac{5}{17}\right):\dfrac{8}{3}\)

=\(\dfrac{8}{17}:\dfrac{8}{3}\)

\(=\dfrac{3}{17}\)

\(\dfrac{13}{17}:\dfrac{8}{3}-\dfrac{5}{17}:\dfrac{8}{3}=\dfrac{13}{17}.\dfrac{3}{8}-\dfrac{5}{17}.\dfrac{3}{8}=\dfrac{3}{8}\left(\dfrac{13}{17}-\dfrac{5}{17}\right)=\dfrac{3}{8}.\dfrac{8}{17}=\dfrac{3}{17}\)

= 3/8 x (5/4 + 3/4)
= 3/8 x 8/4
= 3/8 x 2
= ...........

3/8x[5/4+3/4]

3/8x2

3/4

1/3  x 5/8 + 5/8 x 2/3 = 5/8 x { 1/3 + 2/3} = 5/8 x 9/9 =5/8 x1=5/8 nhé cho mình 1 tích 

 chúc bạn học giỏi

\(\dfrac{1}{3}\times\dfrac{5}{8}+\dfrac{5}{8}\times\dfrac{2}{3}=\dfrac{5}{8}\times\left(\dfrac{1}{3}+\dfrac{2}{3}\right)=\dfrac{5}{8}\times1=\dfrac{5}{8}\)

= 3/5 * 5/3 * 8/27

= 1 * 8/27

= 8/27

xin tiick

3/5x8/27x5/3

=(3/5x5/3)x8/27

=1x8/27=8/27

HT

\(\frac{3}{5}\cdot\frac{8}{27}\cdot\frac{5}{3}=\frac{3\cdot8\cdot5}{5\cdot3\cdot27}=\frac{8}{27}\)

2/15 x 3/8 + 3/8 x 2/3 + 3/8 : 5

= 2/15 x 3/8 + 3/8 x 2/3 + 3/8 x 1/5

= 3/8 x ( 2/15 + 2/3 + 1/5 )

= 3/8 x 1

= 3/8

~ Hok tốt ~

#Minh#

\(\frac{2}{15}\cdot\frac{3}{8}+\frac{3}{8}\cdot\frac{2}{3}+\frac{3}{8}:5\)

\(=\frac{3}{8}\cdot\left(\frac{2}{15}+\frac{2}{3}+1\right):5\)

\(=\frac{3}{8}\cdot\frac{9}{5}:5=\frac{27}{100}\)

3/5 x 8/27 x 5/3

= (3/5 x 5/3) x 8/27

= 1 x 8/27

= 8/27

3/5 x 8/27 x 5/3

= (3/5 x 5/3) x 8/27

= 1 x 8/27

= 8/27

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