4 x 126 x 25

=(4 x 25 ) x 26

= 100 x 26

=12600

(9 x 8 - 12 - 5 x 12) x ( 1+ 2 + 3 + 4+5)

=(72 - 12 - 60) x 15

= (60 - 60) x 15

=0 x 15

=0 

2.tính nhanh

a) a=1-2-3+4+5-6-7+8...+2122-23+24

b)-(7111-53)+(711-153)

c) - 43.(-1-296)-296.43

d)(x - 4).2.6.25.(-7).5

six

a.x

b.v

c.v

d.x

house

n

p

i

10