Question

[Pham Trong Bach]

Tính nhanh:

a)  5 7 ⋅ 10 11 + 5 7 ⋅ 14 11 − 5 7 ⋅ 17 11

b)  1 3 ⋅ 4 5 + 1 3 ⋅ 1 1 5 − − 2 3 1

Answer 1

[Cao Minh Tâm]

a)

5 7 ⋅ 10 11 + 5 7 ⋅ 14 11 − 5 7 ⋅ 17 11 = 5 7 10 11 + 14 11 − 17 11 = 5 7 .1 = 5 7

b)

1 3 ⋅ 4 5 + 1 3 ⋅ 1 1 5 − − 2 3 1 = 1 3 ⋅ 4 5 + 1 3 ⋅ 6 5 + 2 3 = 1 3 4 5 + 6 5 + 2 3 = 1 3 .2 + 2 3 = 4 3