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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“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?”
Full guide and materials
- Activity. Add and subtract within 20 using strategies such as making ten, decomposing a number leading to ten, and using known facts
What to notice. Solve 8 + 6 using making ten: 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
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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?
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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Learning resources
Reviewed external links that reinforce this concept. They do not replace Gakuva’s teaching approach.
Topmarks · Practice link — not the full lesson
Robot Addition
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.
Free · no login · ads
Review and open practice
Save a screenshot from Addition to 20 mode plus a parent note describing one making-ten or known-fact strategy the learner used.
Opening this link does not save learning or assess mastery.
Open practice (new tab)Source, access and review 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.
Save a screenshot from Addition to 20 mode plus a parent note describing one making-ten or known-fact strategy the learner used.
Free · no login · ads
Unknown — link only
Visnos · Practice link — not the full lesson
Addition & Subtraction Facts
Number-line visualization of addition and subtraction facts through 20 for connecting equations to quantities.
Free · no login · no ads observed
Review and open practice
Save a screenshot of an equation within 20 and a parent note that the learner explained the move on the number line.
Opening this link does not save learning or assess mastery.
Open practice (new tab)Source, access and review notes
Number-line visualization of addition and subtraction facts through 20 for connecting equations to quantities.
Save a screenshot of an equation within 20 and a parent note that the learner explained the move on the number line.
Free · no login · no ads observed
Unknown — link only
Toy Theater · Practice link — not the full lesson
Math Mine Addition Subtraction
Solve addition and subtraction equations and clear numbered blocks. Keep problems within 20 and pause to name the strategy used.
Free · no login · ads
Review and open practice
Save a Problems Solved screenshot plus a parent note of correct addition and subtraction examples within 20.
Opening this link does not save learning or assess mastery.
Open practice (new tab)Source, access and review notes
Solve addition and subtraction equations and clear numbered blocks. Keep problems within 20 and pause to name the strategy used.
Save a Problems Solved screenshot plus a parent note of correct addition and subtraction examples within 20.
Free · no login · ads
Unknown — link only
Check understanding
- Solve 8 + 6 using making ten: 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 6–7
Standards