11+ Maths: Adding and Subtracting Decimals
19 October 2026
Practising adding and subtracting decimals
Adding and subtracting decimals is a key skill for the 11+ maths exam. With a bit of guidance, children can master this topic and feel more confident tackling exam questions.
How to line up decimals
When adding or subtracting decimals, always write the numbers so the decimal points are exactly underneath each other. This keeps the place values in order and helps avoid mistakes.
A simple worked example
For example, to solve 3.5 + 2.4, write the numbers in columns with the decimal points lined up. Add as usual: 3.5 + 2.4 = 5.9.
Subtracting decimals with borrowing
If you need to subtract and the top digit is smaller than the bottom, borrow from the next column just as you would with whole numbers. For example, 5.2-3.8 means you borrow to subtract the tenths.
Key insight: Encourage your child to always check their answer by estimating. Rounding each number to the nearest whole can help spot mistakes quickly.
Building confidence for the 11+
Practise with a mix of straightforward sums and word problems. This helps children apply their skills in different contexts, just as they will in the exam.
