Question

Tính nhẩm:  

2 × 7               2 × 2               2 × 6               2 × 3               2 × 10

2 × 5               2 × 9               2 × 4               2 × 1               2 × 8

Answer 1

2 × 7 = 14          2 × 2 = 4            2 × 6 = 12          2 × 3 = 6        2 × 10 = 20

2 × 5 = 10          2 × 9 = 18          2 × 4 = 8           2 × 1 = 2          2 × 8 = 16