Distance on the plane

Target: Find a vertical distance as an absolute difference.

Language target: Call the answer a distance, not a signed move.

Likely miss: Students subtract and keep a negative distance, or add the coordinates.

Ask: The points share which coordinate?

If you see it: Distance is the absolute value of the difference of the changing coordinate.

Evidence to listen for: The student reports a positive horizontal or vertical distance.

Next: If the distance is negative, ask whether a length can point backward.

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