# CCSS.1.OA.D.8

unknowns, equations, addition, subtraction; solve, calculate.

System: US Common Core Math
Route: /math/standards/us-ccss/curratom-us-ccss-1-oa-d-8
Skills: 2

## Skills and Examples

- [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