Mathematics·Addition & Subtraction·procedural
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
Suggested ages 6–7
Learning journey
Your child is building strong foundations in addition and subtraction — learning to add and subtract numbers fluently within 20, understanding the relationship between these operations, and applying various mental strategies to solve problems.
Evidence of 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
Assessment prompt
If Addition and subtraction within 20 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?
Standards alignment
1.OA.6US · ccss-math
Add and subtract within 20
Common Core State Standards for Mathematics · 1