Inverse: addition undoes subtraction
Recognise and use the inverse relationship between addition and subtraction to check calculations and solve missing-number problems
Teaching approaches
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1 approach
If your child works out 13 + 5 = 18, can they immediately use that to say '18 − 5 = 13' — without having to work the subtraction out all over again?
Recognise and use the inverse relationship between addition and subtraction to check calculations and solve missing-number problems
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Learning resources
Reviewed external links that reinforce this concept. They do not replace Gakuva’s teaching approach.
Number Bonds — adult-guided supplementary tool
Use a number-bond diagram with an adult to explore how addition and subtraction undo one another. Place the whole and its two parts, then say the related equations.
Proof: Adult-guided supplementary tool; a manipulative, not an automatically marked game. No automatic correctness feedback, saved progress, or independent learner explanation was established. Parent prompt: “We have 9 altogether and one part is 4. What is the missing part? Show 4 + 5 = 9, then use 9 − 4 = 5 to check. Explain how subtraction undoes the addition.”
Explore the learning path
1 before · 3 after
This concept
Check understanding
- Check 15 + 7 = 22 by calculating 22 − 7 = 15
- Use the inverse to solve: □ + 9 = 14, so □ = 14 − 9 = 5
- Explain that addition and subtraction 'undo' each other
“If your child works out 13 + 5 = 18, can they immediately use that to say '18 − 5 = 13' — without having to work the subtraction out all over again?”
Curriculum record
- Type
- Conceptual
- Subject
- Mathematics
- Domain
- Addition & Subtraction
- Age range
- Ages 6–7
Standards