Multiply and divide by powers of ten for 11+ maths
21 October 2026
Multiply and divide by powers of ten
Understanding how to multiply and divide by powers of ten is a key skill for the 11+ maths exam. Mastering this helps children work quickly and accurately with both whole numbers and decimals.
Multiplying by powers of ten
To multiply a number by 10, 100, 1000 and so on, move the decimal point to the right by as many places as there are zeros. Each zero means one place to the right. For whole numbers, this simply adds zeros. For decimals, it changes the place value.
Worked example
4.5 × 100
Start with 4.5. Move the decimal two places to the right (because there are two zeros in 100). The answer is 450.
Dividing by powers of ten
To divide a number by 10, 100, 1000 and so on, move the decimal point to the left by as many places as there are zeros. This makes the number smaller, and is the reverse of multiplying.
Worked example
360 ÷ 100
Start with 360. Move the decimal two places to the left. The answer is 3.6.
Summary
Practising these steps helps children to handle calculations with confidence, spot patterns, and avoid common mistakes in the 11+ exam.
Key insight: Regular practice with powers of ten builds speed and accuracy, making it easier for children to solve a wide range of maths questions in the 11+ exam.
