Multiply by 25

Divide by 4 and add two zeros.

The question

What is 36 × 25?

The trick

Divide the number by 4, then multiply by 100 by adding two zeros.

Worked example

136 ÷ 4 = 9
2Add two zeros: 900

So: 900

Remember it like this

Four quarters make a rupee. So quarter it, then make it a hundred.

In the exam

The same idea covers 50 (halve, add two zeros) and 125 (divide by 8, add three zeros). If the number doesn't divide by 4 exactly, the remainder becomes .25, .5 or .75 before the zeros.

Why it works

25 is 100 ÷ 4. Dividing by 4 first keeps the numbers small, and multiplying by 100 costs nothing.

Explain this to my childGet the words to teach it, in your language

Try it yourself

0/4 correct

1
48 × 25
48 × 25
2
16 × 25
16 × 25
3
84 × 25
84 × 25
4
32 × 25
32 × 25