Doubling and halving

Doubling is ×2; halving is ÷2. Both are KS1 mental-strategy core skills.

Doubling and halving sit alongside number bonds as the most-used KS1 facts. They scaffold the 2 times table, fractions (a half is one of two equal parts), and more advanced multiplication strategies later.

Worked examples

Doubles to 10: 1+1=2, 2+2=4, 3+3=6, 4+4=8, 5+5=10.

Doubles to 20: 6+6=12, 7+7=14, 8+8=16, 9+9=18, 10+10=20.

Halving (even numbers only): half of 10 = 5; half of 18 = 9; half of 30 = 15.

Frequently asked questions

Can odd numbers be halved?

Yes — but the answer is a fraction. Half of 7 is 3½. KS1 stays with whole-number halves; fractions of odd numbers come in Year 3/4.

Doubling for any number?

Year 2 extends to doubles of multiples of 5 and 10 to 100 (e.g. double 35 = 70). Use partitioning: double 30 + double 5.

Is halving the same as dividing by 2?

Yes — algebraically identical. KS1 uses ‘halve’ or ‘half of’; the ÷ symbol comes later.