Estimate sums using estimate and check: Example question
30 October 2026
When your child is learning to add numbers, it's helpful to estimate the answer before working it out exactly. The estimate and check method teaches children to round numbers first, then compare their estimate with the real answer. This builds confidence and helps spot mistakes early.
Worked example
Question
Estimate and check: 47 + 36
Step 1: Round each number to the nearest 10.
47 rounds to 50.
36 rounds to 40.
Step 2: Add the rounded numbers to estimate the sum.
50 + 40 = 90
Step 3: Add the original numbers to check the real answer.
47 + 36 = 83
Step 4: Compare your estimate and the real answer.
The estimate is 90. The real answer is 83.
Key insight: Estimating helps you check if your answer is sensible.
The correct answer is 83.
After seeing this example, your child will be able to round numbers, add them to estimate a sum, and check their answer. The next step is to practise with similar sums using the same method, so your child can feel sure their answers make sense.
