Year 6 Arithmetic (SATs) · Mental arithmetic · Summary
Year 6 Arithmetic (SATs) Mental arithmetic: summary and key words
Part of the Year 6 Arithmetic (SATs) mental arithmetic chapter. Chapter overview · whole chapter on one page
Chapter summary
| Skill | Method |
|---|---|
| Add large numbers | Split into thousands and the rest: 12,500 + 8,700 = 21,200. |
| Subtract large numbers | Round the number taken away, subtract, then correct. |
| Times tables | Know 12 × 12 by heart; split 12 into 10 and 2 for 12 × 9 = 108. |
| Doubling and halving | Double or halve each part; 3,450 doubled is 6,900. |
| Powers of 10 | × 10 moves digits one place left; × 100 two places left. |
| Decimals | Line up the points, or think in pence: 3.5 + 2.75 = 6.25. |
| Fraction of amount | Divide by the bottom, multiply by the top: 2/5 of 45 = 18. |
Can you…?
- I can add and subtract large numbers in my head by splitting or rounding
- I know the times tables to 12 × 12 and can use them for other facts
- I can double, halve and multiply by 10 and 100 in my head
- I can add, subtract, multiply and divide simple decimals in my head
- I can find a fraction of an amount in my head
- I can estimate to check that my answer is sensible
Key terms
- mental method
- a way of working out a calculation in your head
- round
- to change a number to a friendly number close to it
- double
- multiply by 2
- halve
- divide by 2
- estimate
- a sensible rounded answer used to check a calculation