standard_description: Explain why addition and subtraction strategies work, using place value and the properties of operations. (Explanations may be supported by drawings or objects.)
problem_activity: Stage 2: Three-digit Numbers
Required Preparation
Materials to Gather
Number cards 0–10
Materials to Copy
Blackline Masters
Mystery Number Stage 2 Directions

Narrative
Students pick three cards and make a mystery three-digit number. Students give clues based on the sentence starters.


aligns: no