Curriculum placement
Grade 2. This describes the skill, not a learner estimate.
Sums and differences on a number line
Represent sums and differences as number-line moves
Problem types
- Hop on a number line
- Find the length of a hop
- Which story matches the jumps?
Builds on
- Subtracting within 100
- Counting on and counting back · Earlier idea
Counting on and back is the same as hopping forward and back along a number line.
Leads to
Related skills
- Measuring length with a ruler · Related idea
A ruler is a number line: the length of an object is the distance between two marks, found as a difference.
- Rounding whole numbers · Related idea
A number line cut into equal steps shows where a number lies between two hundreds. The halfway mark is what decides which hundred a number rounds to.
- Regrouping within 1,000 · Shared foundations
- Two-step word problems · Shared foundations
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