Question

 số 1 : tính nhanh 

A = 78 x 31 + 78 x 24 + 78 x 17 + 22 x 72

C = 53 x 39 + 47 x 39 - 53 x 21 - 47 x 21

B = 35 x 34 + 35 x 86 + 65 x 75 + 65 x 45

D = 27 x 332 + 68 x 27 + 73 x 332 + 68 x 73

E = 2 x 53 x 12 + 4 x 6 x 37 + 2 x 38 x 12

F = 3 x25 x 8 + 4 x 6 x 37 + 2 x 38 x 12

Answer 1

A = 78 x 31 + 78 x 24 + 78 x 17 + 22 x 72

A = 78 x ( 31 + 24 + 17 ) + 22 x 72

A = 78 x 72 + 22 x 72

A = 72 x ( 78 + 22 ) 

A = 72 x 100

A = 7200

C = 53 x 39 + 47 x 39 - 53 x 21 - 47 x 21

C = 39 x ( 53 + 47 ) - 21 x ( 53 - 47 )

C = 39 x 100 - 21 x 6

C = 3900 - 126

C = 3774

Answer 2

ko pc tui thua bn 1 lp 

Answer 3

A = 78 x 31 + 78 x 24 + 78 x 17 + 22 x 72

A = 78 x ( 31 + 24 +17 ) + 22 x 72

A = 78 x 72 + 22 x 72

A = 72 x ( 78 + 22 )

A = 72 x 100

A = 7200

Answer 4

15x6+20x6+45x6+75

Answer 5

A = 78 x 31 + 78 x 24 + 78 x 17 + 22 x 72

A = 78 x ( 31 + 24 + 17 ) + 22 x 72

A = 78 x 72 + 22 x 72

A = 72 x ( 78 + 22 ) 

A = 72 x 100

A = 7200