Question

Bài 2. Tính bằng cách hợp lí nhất:

a) 38. 63 + 37. 38                                                 b) 12.53 + 53. 172– 53. 84

c) 35.34 +35.38 + 65.75 + 65.45                    d)  39.8 + 60.2 + 21.8

e)  36.28 + 36.82 + 64.69 + 64.41

Answer 1

a)38.63+37.38

=38.(63+37)

=38.100

=3800

 

Answer 2

a) \(=38\left(63+37\right)=38.100=3800\)

b) \(=53\left(12+172-84\right)=53.100=5300\)

c) \(=35\left(34+38\right)+65\left(75+45\right)=35.72+65.120=10422\)

d) \(=39.8+15.8+21.8=8\left(39+15+21\right)=8.75=600\)

e) \(=36\left(28+82\right)+64\left(69+41\right)=36.110+64.110=110\left(36+64\right)=110.100=11000\)