126 x ( a - a ) x a x 26

126 x 0 x a x 26

0

126 x (a x 1 - a : 1) x a x 26

= 126 x 0 x a x 26

= 0

126 x ( a x ( 1-1) x a x 26

= 126 x a x 0 x a x 26

= 0 x 26 x a

= 0 x a

= 0

a) 126 x 4 + 126 x 5 + 126

= 126 x 4 + 126 x 5 + 126 x 1

= 126 x ( 4 + 5 + 1 )

= 126 x 10

= 1260

b) 184 x 100 - 50 x 100

= ( 184 - 50 ) x 100

= 134 x 100

= 13400

126 x 4 + 126 x 5 + 126

= 126 x ( 4 + 5 + 1 )

= 126 x 10

= 1260

4 x 126 x 25

= ( 4 x 25 ) x 126

= 100 x 126

= 12600

Đáp án:

4 x 126 x 25

= ( 4 x 25 ) x 126

= 100 x 126

= 12600

Bài 1: Tính nhanh 

A, 13 x 126 + 37 x 126 - 49 x 126

= 126 x ( 13 + 49 - 49 )

= 126 x 1

= 126

B, ( 1 + 2 + 4 + 8+.....+ 512 ) x ( 101 x 102 - 101 x 101 - 50 - 51 )

= ( 1 + 2 + 4 + 8+.....+ 512 ) x ( 101 x ( 102 - 101 - 1))

= ( 1 + 2 + 4 + 8+.....+ 512 ) x ( 101 x 0)

= ( 1 + 2 + 4 + 8+.....+ 512 ) x 0

= 0

a,

b,

 4 x 126 x6

=(4 x 125 + 4 x 1) x 6

=(500 +4)x6

=504 x 6

=3024 

4 x 126 x 6

= 504 x 6

= 3024

Chúc bạn học tốt

4 x 126 x 6

= 4 x 6 x 126

= 24 x 126 

= 3024

a. 4 x 126 x 25

= (4 x 25) x 126

= 100 x 126

= 12600

b. (9 x 8 – 12 – 5 x 12) x ( 1 + 2 + 3 + 4 + 5)

= (72 – 12 – 60) x ( 1 + 2 + 3 + 4 + 5)

= 0 x ( 1 + 2 + 3 + 4 + 5)

= 0