# Estimating by rounding

Estimate the answer to a calculation and use inverse operations to check answers; apply to increasingly large numbers using rounding and inverse reasoning

Builds on: Inverse: addition undoes subtraction (hard, https://ai.page/c/inverse-addition-undoes-subtraction/en.md), Addition and subtraction within 1000 (soft, https://ai.page/c/addition-and-subtraction-within-1000/en.md)

Concept id: estimating-by-rounding. Subject: maths. Licence: CC BY-SA 4.0.

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