Tricks · Multiplying

Multiply by 25

Any number times 25. Easiest when the number divides by 4, such as 36 × 25 or 48 × 25.

n × 25

The trick, step by step

Divide by 4: 36 ÷ 4 = 9.
Multiply by 100: 9 × 100 = 900.
So 36 × 25 = 900. If the number does not divide by 4, multiply by 100 first: 37 × 25 = 3700 ÷ 4 = 925.

given working answer taken away

25 is 100 ÷ 4, so n × 25 = n × 100 ÷ 4, and the ÷ 4 can come first or last. Four 25s make 100, just as four quarters make a rupee.