Question

Tinh nhanh:

a) 2.31.12+4.6.42+8.27.3

b) 36.28+36.82+64.69+64.41

Answer 1

2.31.12+4.6.42+8.27.3

=24.31+24.42+24.27

=24.(31+42+27)

=24.100

=2400

Answer 2

36.28+36.82+64.69+64.41

=36.(28+82)+64.(69+41)

=36.100+64.100

=(36+64).100

=100.100

=10000

Answer 3

a) 2.31.12+4.6.42+8.27.3

   = (2.12) .31+ ( 4.6) .42+(8.3).27

   = 24.31+24.42+24.27

   =24.(31+42+27)

   =24.100

   =2400

b)36.28+36.82+64.69+64.41

 =36.(28+82)+64.(69+41)

 =36.110+64.110

 =110.(36+64)

 =110.100

 =11000