Mathematics
Mathematical Thinking
Meta
8–9 yrs
Justifying mathematical reasoning (age 8+)
数学推理论证（8岁以上）
Description
Construct and present multi-step mathematical arguments; critique the reasoning of others and explain clearly why a method works or fails
Mastery Evidence
- Explain why 1/3 > 1/5 using the idea that more parts means smaller pieces
- Find and explain an error in a peer's column subtraction with exchanges
- Present a chain of reasoning: since 6×8=48 and 6×2=12, then 6×10=60 so 6×8=60−12=48
Assessment Prompt
If a classmate claims "you can't multiply a fraction and get a bigger answer", can your child think through whether that's always true — and give an example to support or challenge the claim?
