# CCSS.2.OA.A.1

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

System: US Common Core Math
Route: /math/standards/us-ccss/curratom-us-ccss-2-oa-a-1
Skills: 4

## 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 Sub Word Problems Two Step](/math/skills/oa/add-sub-word-problems-two-step) — Operations Models, Bar Models, and Word Problems
- [Equations Unknown Add Sub](/math/skills/oa/equations-unknown-add-sub) — Equations, Variables, Expressions, and Inequalities
- [Variable As Unknown](/math/skills/prealg/variable-as-unknown) — Equations, Variables, Expressions, and Inequalities