Question

tính bằng cách thuận tiện nhất : 
4 x 26 x 25                          63 x 78 - 53 x 78 
 

67 x 92 + 67 x 8                  8 x 23 x 25 x 125 

Answer 1

a: =100x26=2600

b: =78x10=780

c: =67x100=6700

d: =1000x575=575000

Answer 2

\(4\times26\times25=\left(4\times25\right)\times26=100\times26=2600\\ 63\times78-53\times78=\left(63-53\right)\times78=10\times78=780\\ 67\times92+67\times8=67\times\left(92+8\right)=67\times100=6700\\ 8\times23\times25\times125=\left(8\times125\right)\times\left(23\times25\right)=1000\times575=57500\)

Answer 3

a: =100x26=2600

b: =78x10=780

c: =67x100=6700

d: =1000x575=575000