# CCSS.2.OA.B.2

addition facts, subtraction facts, mental strategies; calculate, fluently compute.

System: US Common Core Math
Route: /math/standards/us-ccss/curratom-us-ccss-2-oa-b-2
Skills: 2

## Skills and Examples

- [Add Within 20 Strategies](/math/skills/oa/add-within-20-strategies) — Whole-Number Operations and Fact Fluency
- [Sub Within 20 Strategies](/math/skills/oa/sub-within-20-strategies) — Whole-Number Operations and Fact Fluency