Every plus task has a matching minus task, and the other way around!
From plus to minus:
3 + 4 = 7 → 7 − 4 = 3
From minus to plus:
9 − 5 = 4 → 4 + 5 = 9
Always write the matching reverse task next to it.
Find the matching reverse task. The numbers shown give the answer.
Example
What does this exercise practice?
This task shows that plus and minus are reverse operations; anyone who understands this can check their work and find mistakes on their own.
Common pitfalls
Children often just flip the operation signs but mix up the positions of the numbers. Saying it out loud helps: 7 minus 4 makes 3, so 3 plus 4 equals 7.
How to practice at home
With building blocks: lay out 5 bricks, take 2 away, count. Then put them back: how many do we need to add to have 5 again? Hands-on action makes the reverse visible.
Related: Calculation, Swap