Expressions in context

Target: Write and evaluate an expression for a starting amount plus a rate.

Language target: Say what the variable counts.

Likely miss: Students evaluate an expression before writing one that matches the story.

Ask: What does the variable count in this story?

If you see it: Write the expression with the variable still visible, then substitute.

Evidence to listen for: The expression and the story describe the same operations.

Next: If the number appears too soon, cover the value of the variable and write the expression first.

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