Question

What if she knows 3 × 10 =30, how
.
can she find 3 × 5 = ?

Answer 1

The same way as the question before.

5 × 2 = 10 which means 10 ÷ 2 = 5

3 × 5 = (3 x 10)÷2

3 x 10 = 30

30 ÷ 2 = 15

3 × 5 = 15