Question

Tính nhẩm:

 a, 9 × 5

 b, 72 ÷ 9

 c, 9 × 8

   d, 81 ÷ 9

Answer 1

    a, 9 × 5 = 45

 b, 72 ÷ 9 = 8

 c, 9 × 8 = 72

   d, 81 ÷ 9 = 9