1,8 x 54 + 29 x 1,8 + 0,2 x 17 x 9

= 1,8 x 54 + 29 x 1,8 + ( 0,2 x 9 ) x 17

= 1,8 x 54 + 29 x 1,8 + 1,8 x 17

= 1,8 x ( 54 + 29 + 17 )

= 1,8 x 100

= 180

1,8 x 54 + 29 x 1,8 + 0,2 x 17 x 9

 = 1,8 x 54 + 29 x 1,8 + ( 0,2 x 9 ) x 17  

= 1,8 x 54 + 29 x 1,8 + 1,8 x 17

= 1,8 x ( 54 + 29 + 17 )  

= 1,8 x 100

= 180             

a) = \(\left(\dfrac{2}{7}+\dfrac{4}{7}+\dfrac{1}{7}\right):\dfrac{27}{31}\)

= \(\dfrac{7}{7}\) x \(\dfrac{31}{27}\)

= 1 x \(\dfrac{31}{27}\) = \(\dfrac{31}{27}\)

b) = \(\left(\dfrac{23}{45}:\dfrac{23}{45}\right)\)x \(\dfrac{17}{51}\)

= 1 x \(\dfrac{17}{51}\)= \(\dfrac{17}{51}\)

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

=8/17:8/3

=3/17

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

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

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

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

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

Câu 2:Đáp số là 8/17 nhé

(5/9+4/9)x8/17

=>1x8/17=8/17

Câu 1: Tìm x:

a)  2/5× x =(thiếu đề)

 8/7: x =4/5 

x=8/7:4/5

x=10/7

Câu 2: Tính bằng cách thuận tiện nhất

5/9× 8/17 + 4/9 × 8/17

=(5/9+4/9)x8/17

=1x8/17=8/17

= (9-8)+(7-6)+(5-4)+(3-2)+(1-0)

=    1  + 1   +  1   +   1   +  1

= 1x5 = 5

(k nha!!!)

Bằng 5 nha

`4/6+7/13+17/9+19/13+1/9+14/6`

`=(4/6+14/6)+(7/13+19/13)+(17/9+1/9)`

`=18/6+26/13+18/9`

`=3+2+2`

`=7`

\(\dfrac{2}{3}+\dfrac{7}{13}-\dfrac{17}{9}+\dfrac{19}{13}-\dfrac{1}{9}+\dfrac{7}{3}\)

\(=\left(\dfrac{2}{3}+\dfrac{7}{3}\right)+\left(\dfrac{7}{13}+\dfrac{19}{13}\right)-\left(\dfrac{17}{9}+\dfrac{1}{9}\right)\)

\(=\dfrac{9}{3}+\dfrac{26}{13}-\dfrac{18}{9}\)

\(=3+2-2\)

\(=3\)

giúp e với mn ơi

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