Bài 2: Tính bằng 2 cách: a) ( 2/3 x 4/5 ) x 5/6=………………………………………………. =………..

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1. a) ( 2/3 x 4/5 ) x 5/6=

   Cách 1: a) ( 2/3 x 4/5 ) x 5/6= 8/15 x 5/6 = 4/9

   Cách 2: a) ( 2/3 x 4/5 ) x 5/6= 2/3 x 4/5 x 5/6 = 2/3 x(4/5 x 5/6)=2/3 x 2/3 = 4/9

   c) ( 1/2 x 1/3 ) x 1/5

   Cách 1: c) ( 1/2 x 1/3 ) x 1/5 = 1/6 x 1/5 = 1/30

   Cách 2: c) ( 1/2 x 1/3 ) x 1/5 = 1/2 x 1/3  x 1/5 = (1/2 x 1/5) x 1/3 = 1/10 x 1/3 = 1/30

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2. a, (2/3 x 4/5)x5/6                  

   = 8/15 x 5/6

   = 40/90=4/9

    Cách 2

   (2/3 x 4/5)x5/6

   = 2/3 x (4/5×5/6)

   = 2/3 x 20/30

   = 40/90=4/9

   b,Giống a ko làm

   c, (1/2 x 1/3) x 1/5

   =1/6 x 1/5

   = 1/30

   Cách 2

   (1/2 x 1/3) x 1/5

   = 1/2 x (1/3 x 1/5)

   = 1/2 x 1/15

   = 1/30

   d,giống c nhé

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