Double number lines

Target: Read paired values on a double number line.

Language target: Say which tick marks are paired.

Likely miss: Students pair tick marks that are the same distance in centimeters on the page rather than the same number of ratio jumps.

Ask: How many jumps from zero is this pair?

If you see it: Have the student underline both products and name the shared factor before computing.

Evidence to listen for: Both cells in a new row come from the same factor.

Next: Return to a double number line if addition appears. Otherwise compare two ratios.

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