Rate of change

Target: State how much y changes when x increases by 1.

Language target: Say “increases by.”

Likely miss: Students say y increases by the constant instead of by the coefficient.

Ask: What stays fixed when x grows by 1?

If you see it: Ask what happens to y when x increases by 1.

Evidence to listen for: The student names the coefficient as the change in y.

Next: Build one more row of the table if the change is described as the total.

Observable student moves: names both quantities, uses the represented relationship, and revises after feedback. This companion is not a score.