# CCSS.1.OA.A.1

addition, subtraction, word problems, unknowns; solve, model, represent.

System: US Common Core Math
Route: /math/standards/us-ccss/curratom-us-ccss-1-oa-a-1
Skills: 5

## Skills and Examples

- [Add Sub Word Problems One Step](/math/skills/oa/add-sub-word-problems-one-step) — Operations Models, Bar Models, and Word Problems
- [Add Within 20 Strategies](/math/skills/oa/add-within-20-strategies) — Whole-Number Operations and Fact Fluency
- [Bar Model Comparison](/math/skills/oa/bar-model-comparison) — Operations Models, Bar Models, and Word Problems
- [Bar Model Part Whole](/math/skills/oa/bar-model-part-whole) — Operations Models, Bar Models, and Word Problems
- [Sub Within 20 Strategies](/math/skills/oa/sub-within-20-strategies) — Whole-Number Operations and Fact Fluency