Question

[Pham Trong Bach]

Tính hợp lý

a)  3 8 − 6 18 + 9 27 + 2 16

b)  13 26 − 1 3 − 1 2 + 7 21

Answer 1

[Cao Minh Tâm]

a)

3 8 − 6 18 + 9 27 + 2 16 = 3 8 + 2 16 + − 6 18 + 9 27 = 6 16 + 2 16 + − 18 54 + 18 54 = 1 2 + 0 = 1 2

b)

13 26 − 1 3 − 1 2 + 7 21 = 1 2 − 1 3 − 1 2 + 1 3 = 1 2 − 1 2 + − 1 3 + 1 3 = 0 + 0 = 0