A) 7 + 3 + 40 – 20 + 60 – 40B) 20 + 60 – (30 + 20) + 40 – (10 + 50)

Bài 2. Tính:

a) 7 + 3 + 40 – 20 + 60 – 40

b) 20 + 60 – (30 + 20) + 40 – (10 + 50)