B

câu -13+18-27 nha

B

b) = 27.(58+42)

    = 27.100=2700

d) =18.(68+39-7)

    =18.100=1800

`b)`

`27.58 + 42.27`

`=27.(58+42)`

`=27.100`

`=2700`

`d)`

`68.18+39.18-18.7`

`=18.(68 + 39-7)`

`=18.100`

`=1800`

Áp dụng  : `a.d + b.d = d.(a+d)`

b) 27.58+42.27=27.(58+42)=27.100=2700

d)68.18+39.18-18.7=18.(68+39-7)=18.100=1800

a: =8/5-2/3=24/15-10/15=14/15

12/20-6/18=3/5-1/3=9/15-5/15=4/15

b: 18/21-12/27=6/7-7/9=54/63-49/63=5/63

8/12-20/50=2/3-2/5=10/15-6/15=4/15

\(a,\dfrac{8}{5}-\dfrac{18}{27}=\dfrac{8}{5}-\dfrac{2}{3}=\dfrac{14}{15}\\ \dfrac{12}{20}-\dfrac{6}{18}=\dfrac{3}{5}-\dfrac{1}{3}=\dfrac{4}{15}\\ b,\dfrac{18}{21}-\dfrac{12}{27}=\dfrac{6}{7}-\dfrac{4}{9}=\dfrac{26}{63}\\ \dfrac{8}{12}-\dfrac{20}{50}=\dfrac{2}{3}-\dfrac{2}{5}=\dfrac{4}{15}\)

A

A

A

13/18

=13/18x(41/27-14,27)

=13/18x1

=13/18

41/27*13/18-13/18*14/27

41/27*       0        *14/27=

         0               *14/27=0

18 : 9 = 2

27 : 9 = 3

36 : 9 = 4

45 : 9 = 5

18 : 2 = 9

27 : 3 = 9

36 : 4 = 9

45 : 5 = 9

41 / 27 x 13 / 18 - 13 / 18 x 14 / 27 =  ( 41 / 27 - 14 / 27 ) x 13 / 18 = 27 / 27 x 13 / 18 = 1 x 13 / 18 = 13 / 18

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