Justifying mathematical reasoning (age 8+)
Construct and present multi-step mathematical arguments; critique the reasoning of others and explain clearly why a method works or fails
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“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?”
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- Activity. Construct and present multi-step mathematical arguments; critique the reasoning of others and explain clearly why a method works or fails
What to notice. 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
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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?
Construct and present multi-step mathematical arguments; critique the reasoning of others and explain clearly why a method works or fails
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Check understanding
- 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
“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?”
Curriculum record
- Type
- Meta
- Subject
- Mathematics
- Domain
- Mathematical Thinking
- Age range
- Ages 8–9