standard_description: Identify when two expressions are equivalent (i.e., when the two expressions name the same number regardless of which value is substituted into them). For example, the expressions y + y + y and 3y are equivalent because they name the same number regardless of which number y stands for.
problem_activity: Stage 5: Cover (up to 20)
Required Preparation
Materials to Gather
Cups
Two-color counters
Materials to Copy
Blackline Masters
Shake and Spill Stage 4 and 5 Recording Sheet (G1 and 2)

Narrative
Students decide together how many counters, between 11–20, to use. Partner A closes their eyes while Partner B shakes, spills, and covers up the yellow counters with a cup. Partner A determines how many counters are under the cup and explains how they know. Both partners record the round. Switch roles and repeat.
Additional Information
Each group of 2 needs a cup and 20 two-color counters.


aligns: no