Estimating by rounding
Mathematics · Addition & Subtraction · meta
Estimate the answer to a calculation and use inverse operations to check answers; apply to increasingly large numbers using rounding and inverse reasoning
What mastery looks like
- Round numbers to the nearest 10 or 100 to estimate a sum or difference before calculating
- Use addition to check a subtraction answer, or vice versa
- Identify when a calculated answer is unreasonable based on the estimate
- Round numbers to estimate a sum or difference before calculating
- Use addition to check a subtraction answer and vice versa
- Identify an unreasonable answer by comparing to the estimate
Check your understanding
Before Estimating by rounding works out a calculation, can they make a sensible rough guess — and then check their answer using the opposite operation?
Prerequisites
Required first
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