Mixed operations with missing numbers: step-by-step example
22 October 2026
When your child sees a maths question with a missing number and several different operations, it can feel confusing at first. Using the BIDMAS order helps to break the problem into clear steps, so your child can work out which part to tackle first.
Worked example
7 × □ - 5 = 23
First, add 5 to both sides to undo the -5.
7 × □ = 28
Next, divide both sides by 7 to find the missing number.
□ = 4
The correct answer is 4.
After working through this example, your child will know how to find a missing number in a mixed operation question. They will be ready to try similar questions and build confidence for their 11+ practice. For more support, you can find resources by searching for maths.com uk.
