Addition and subtraction within 20
Add and subtract within 20 using strategies such as making ten, decomposing a number leading to ten, and using known facts
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Addition and subtraction within 20 means solving sums and differences to 20 with strategies—not only counting every object from one. Making ten (8 + 5 → 8 + 2 + 3), decomposing to reach ten (13 − 4 → 13 − 3 − 1), and using a known fact (9 + 9 = 18 so 9 + 8 = 17) are the moves. We will model one of each, then try a short mixed set.
Spend about 12 minutes practising addition and subtraction within 20 with counters and written equations, using make-ten and related-fact strategies, then checking two fresh problems.
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Learning resources
Extra practice links — they do not replace Gakuva’s teaching approach.
Topmarks · Practice link — not the full lesson
Robot Addition
Before you open · source notes
Addition matching with an Addition to 20 mode for facts within 20. Pair with adult talk about making ten or using a known fact when a level feels hard.
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Before you openSave a screenshot from Addition to 20 mode plus a parent note describing one making-ten or known-fact strategy the learner used.
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Visnos · Practice link — not the full lesson
Addition & Subtraction Facts
Before you open · source notes
Number-line visualization of addition and subtraction facts through 20 for connecting equations to quantities.
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Before you openSave a screenshot of an equation within 20 and a parent note that the learner explained the move on the number line.
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Toy Theater · Practice link — not the full lesson
Math Mine Addition Subtraction
Before you open · source notes
Solve addition and subtraction equations and clear numbered blocks. Keep problems within 20 and pause to name the strategy used.
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Before you openSave a Problems Solved screenshot plus a parent note of correct addition and subtraction examples within 20.
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Check understanding
- Solve 8 + 6 using making ten, e.g. on a real or on-screen double ten frame: 8 + 2 + 4 = 14
- Solve 13 − 4 by decomposing: 13 − 3 − 1 = 9
- Use a known fact (8 + 4 = 12) to derive 12 − 8 = 4
“If your child needs to work out '8 + 6', can they split the 6 into 2 + 4, use the 2 to fill up to 10, then add the remaining 4 to get 14?”
Curriculum record
- Type
- Procedural
- Subject
- Mathematics
- Domain
- Addition & Subtraction
- Age range
- Ages 6–8
Standards