Mathematics · Grades 2–4
Balance two sides
Work out one side, then subtract the known part.
The key idea
Work out one side, then subtract the known part.
a + □ = b + c
Worked examples
Find the missing number: 22 + □ = 13 + 41.
13 + 41 − 22 = 32
32
Find the missing number: 24 + □ = 20 + 24.
20 + 24 − 24 = 20
20
Try it yourself
Find the missing number: 26 + □ = 3 + 27.
Find the missing number: 8 + □ = 6 + 40.
Check your understanding
Answers and marking notes
- 4
3 + 27 − 26 = 4
- 38
6 + 40 − 8 = 38
Further reading and review references
These are reference links, not copied exercises, institutional endorsement or proof of independent review.
Learning preview · teacher review required. Grade bands are approximate, not official curriculum alignment.