How to Multiply by 5 in Your Head

Updated 4 October 2026

Multiply by 5 by halving, then adding a zero.

48 × 5 = 240

How do you multiply by 5 in your head?

To multiply by 5, halve the number and add a zero. For 48 × 5, half of 48 is 24, and 24 × 10 = 240. It works because 5 is half of 10, so five of something is ten of them halved, and halving first keeps the numbers small. An odd number halves to a decimal, and the added zero clears it: 47 × 5 = 23.5 × 10 = 235. So an odd number times 5 always ends in 5, and an even one ends in 0, which is a quick check on any answer. Larger numbers take the same steps: 364 × 5 = 182 × 10 = 1820. When halving the whole number is awkward, halve it in parts: 74 is 70 + 4, which halves to 35 + 2 = 37, so 74 × 5 = 370. Multiplying by 50 is the same trick with two zeros: 64 × 50 = 32 × 100 = 3200.

1. 5 is half of 10, so take half of 48 first, then ten of that.

2. Halve: 48 ÷ 2 = 24. Then shift a place: 24 × 10 = 240.

3. An odd number halves to a decimal: 47 ÷ 2 = 23.5, and 23.5 × 10 = 235.

What about bigger numbers?

Halving first keeps the numbers small at every step. For 248 × 5, half of 248 is 124, and 124 × 10 = 1240. For 1250 × 5, half of 1250 is 625, so 6250. When the halving is awkward, split first: 136 is 100 + 36, the halves are 50 + 18 = 68, and 68 × 10 = 680.

Why does it work?

5 is 10 ÷ 2, so multiplying by 5 is multiplying by 10 and dividing by 2, in either order. Halving first is easier because the number is smaller, and multiplying by 10 is only a place-value shift: every digit moves one place to the left.

All 36 shortcuts: the Magic Tricks library.