Question

Tính nhanh:

a, 2 x 31 x 12 + 4 x 6 x 42 + 8 x 27 x3

b, 2 x 53 x 12 + 4 x 6 x 87 -3 x 8 x 40

c, 5 x 7 x 77 -7 x 60 + 49 x 25 - 15 x 42

Answer 1

a, 2 x 31 x 12 + 4 x 6 x 42 + 8 x 27 x 3

= 2 x 12 x 31 + 4 x 6 x 42 + 8 x 3 x 27

= 24 x 31 + 24 x 42 + 24 x 27

= 24 x ( 31 + 24 + 27 )

= 24 x 82 

= 1968

b, 2 x 53 x 12 + 4 x 6 x 87 - 3 x 8 x 40

= 24 x 53 + 24 x 87 - 24 x 40

= 24 x ( 53 + 87 - 40 )

= 24 x 100

= 2400

c, Tương tự

Answer 2

a) = 1968

b) = 2400

đó là kq câu a) ; b)

**** Nha bn

Answer 3

a)  2 x 31 x 12 + 4 x 6 x 42 +  8 x 27 x 3

= 2 x 12 x 31 + 4 X 6 x 42 + 8 x 3 x27

=24 x 31 + 24 x 42 + 24 x 27

= 24 x ( 31 + 24 + 27 )

= 24 x 82

=1968

Answer 4

Tính nhanh:

a, 2 x 31 x 12 + 4 x 6 x 42 + 8 x 27 x3

b, 2 x 53 x 12 + 4 x 6 x 87 -3 x 8 x 40

c, 5 x 7 x 77 -7 x 60 + 49 x 25 - 15 x 42

a, 2 x 31 x 12 + 4 x 6 x 42 + 8 x 27 x 3

= 2 x 12 x 31 + 4 x 6 x 42 + 8 x 3 x 27

= 24 x 31 + 24 x 42 + 24 x 27

= 24 x ( 31 + 24 + 27 )

= 24 x 82 

= 1968

b, 2 x 53 x 12 + 4 x 6 x 87 - 3 x 8 x 40

= 24 x 53 + 24 x 87 - 24 x 40

= 24 x ( 53 + 87 - 40 )

= 24 x 100

= 2400

c, Tương tự