Surface area of prisms

Target: Add the areas of the three pairs of faces.

Language target: Name the three pairs.

Likely miss: Students count only the faces they can see in a picture, or they confuse the net’s area with volume.

Ask: Which face did you count twice, once for each side?

If you see it: Count faces on the net, then compute surface area if the question asks for covering.

Evidence to listen for: The student distinguishes a count of faces from the area of those faces.

Next: Unfold a box if the hidden faces disappear.

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