# Adding and subtracting (age 7+)

Add and subtract numbers with up to three digits using formal written methods of columnar addition and subtraction

Builds on: Fluent adding and subtracting within 100 (hard, https://ai.page/c/fluent-adding-and-subtracting-within-100/en.md), Addition and subtraction within 1000 (hard, https://ai.page/c/addition-and-subtraction-within-1000/en.md)

Concept id: adding-and-subtracting-age-7. Subject: maths. Licence: CC BY-SA 4.0.

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