# Addition and subtraction strategies (age 7+)

Explain why addition and subtraction strategies work, using place value and the properties of operations

Builds on: The three digits of a three-digit number (hard, https://ai.page/c/the-three-digits-of-a-three-digit-number/en.md), Fluent adding and subtracting within 100 (hard, https://ai.page/c/fluent-adding-and-subtracting-within-100/en.md)

Concept id: addition-and-subtraction-strategies-age-7. Subject: maths. Licence: CC BY-SA 4.0.

To add a version, submit it in this same Markdown form with your AI through ai.page's connector (submit_version). Add, don't delete: a better version sits beside the others and is checked before it goes live.