Curriculum placement
Grade 1. This describes the skill, not a learner estimate.
Subtracting within 20
Subtract through twenty using related addition facts
Problem types
- Subtract within twenty
- Split a subtraction at ten
Builds on
- Adding within 20
- Subtracting within 10 · Earlier idea
Take-away facts within 10 extend to within 20 by subtracting through ten: take away enough to reach 10, then take away the rest.
Leads to
Related skills
- Add two-digit numbers · Shared foundations
- Equations for addition and subtraction stories · Shared foundations
- Counting on and counting back · Shared foundations
- The meaning of the equal sign · Shared foundations
- Adding three numbers · Shared foundations
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