11+ Maths: Multiply & Divide by Powers of Ten
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. It helps children work confidently with large and small numbers, decimals, and units.
How it works
When multiplying by 10, 100 or 1000, each digit moves one, two or three places to the left. When dividing by these numbers, each digit moves to the right by the same amount. No numbers are added or lost, just shifted in place value.
Worked example
Let's multiply 4.6 by 100.
Step 1: Start with 4.6. The decimal point is between the 4 and the 6.
Step 2: Because we are multiplying by 100, move every digit two places to the left.
Step 3: The 4 moves from the units to the hundreds place, and the 6 moves from tenths to tens.
Step 4: Fill in any empty places with zeros as needed.
The answer is 460.
Dividing by powers of ten
If we divide 4.6 by 100, we move each digit two places to the right instead. The 4 moves from units to hundredths, and the 6 moves from tenths to thousandths. The answer is 0.046.
Key insight: Encourage your child to visualise the digits moving left for multiplication and right for division, rather than focusing on the decimal point. This helps avoid common mistakes, especially with decimals.
