standard_description: Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.
problem_activity: Stage 2: Numbers 11–19
Required Preparation
Materials to Gather
Connecting cubes
Two-color counters
Materials to Copy
Blackline Masters
Make or Break Apart Numbers Stage 2 Recording Sheet
Make or Break Apart Numbers Stage 2 Number Mat 11-19
Make or Break Apart Numbers Stage 2 Gameboards

Narrative
Students roll to get a number from 11–19. They find two groups of dots that can be put together to make that number. Students write an expression to represent the two parts that make the number.


aligns: no