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10 mental maths tricks for kids (with pictures)

Quick, clever ways to work out sums in your head. Start at the top and work down: each trick gets a little harder.

7 min read · Updated 1 October 2026 · Global Genius League
IN SHORT
  • Mental maths is about clever shortcuts, not counting faster.
  • Learn one trick at a time. Use it for a week before moving on.
  • Every trick has two Try it questions. Cover the answer and have a go!
1

Make a ten

AGES 5+

Tens are easy to add. Borrow from one number to fill up the other to 10.

8 + 5→8 + 2 + 3→10 + 3→13
8 gold dots + 2 green dots fill the ten-frame. 3 are left over: 13.
TRY IT
9 + 4
Answer= 13
7 + 6
Answer= 13
2

Start from the bigger number

AGES 5+

Counting on from the bigger number is faster and makes fewer mistakes.

3 + 9→9 … 10, 11, 12→12
TRY IT
2 + 8
Answer= 10
4 + 7
Answer= 11
3

Doubles and near doubles

AGES 6+

Most children know doubles. If two numbers are next to each other, double one and add 1.

7 + 8→7 + 7 + 1→14 + 1→15
TRY IT
6 + 7
Answer= 13
8 + 9
Answer= 17
4

Split into tens and ones

AGES 7+

Add the tens, add the ones, then put them together.

46 + 38→70 + 14→84
SPLIT46 → 40 + 638 → 30 + 8
→
TENS · ONES40 + 30 = 706 + 8 = 14
→
TOGETHER70 + 14 = 84
Split both numbers, add the tens and the ones, then put them together.
TRY IT
35 + 24
Answer= 59
57 + 26
Answer= 83
5

Round and adjust

AGES 8+

Numbers ending in 9 are nearly a ten. Use the ten, then fix it.

59 + 26→60 + 26 − 1→85
59
round
60
+26
86
−1
85
Round 59 up to 60, add 26 to make 86, then take back the extra 1: 85.
TRY IT
39 + 15
Answer= 54
48 + 29
Answer= 77
6

Take away by adding up

AGES 8+

For numbers close together, hop up from the smaller one and count the hops.

52 − 47→3 + 2→5
47
+3
50
+2
52
Hop from 47 to 50 (3), then to 52 (2). The difference is 5.
TRY IT
63 − 58
Answer= 5
81 − 76
Answer= 5
7

Times 10 and 100

AGES 8+

Every digit moves one place to the left, and a zero fills the gap.

34 × 10→340
BEFORE
34
100s10s1s
→
AFTER
340
100s10s1s
The 3 moves to the hundreds, the 4 to the tens, and 0 fills the ones.
TRY IT
27 × 10
Answer= 270
6 × 100
Answer= 600
8

Times 5: times 10, then halve

AGES 9+

5 is half of 10. Multiply by 10, then cut it in half.

46 × 5→460 ÷ 2→230
TRY IT
24 × 5
Answer= 120
38 × 5
Answer= 190
9

Times 9: times 10, minus one lot

AGES 9+

9 lots is one less than 10 lots.

7 × 9→70 − 7→63
TRY IT
6 × 9
Answer= 54
12 × 9
Answer= 108
10

Double and halve

AGES 10+

Halve one number and double the other. The answer stays the same, but the sum gets easier.

16 × 25→8 × 50→4 × 100→400
TRY IT
14 × 5
Answer= 70
18 × 50
Answer= 900

How to practise these tricks

  • Pick one trick a week. Use it every day, in the car, at the shop, at dinner.
  • Say the steps out loud: “make a ten, then add the rest”.
  • Mix tricks once each one feels easy.
  • Try a timed round in the free Practice Arena, or look at sample questions for your child’s level.
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