# Fluent addition and subtraction (age 9+)

Fluently add and subtract whole numbers with more than four digits using the standard columnar algorithm

Builds on: Adding and subtracting (age 8+) (hard, https://ai.page/c/adding-and-subtracting-age-8/en.md)

Concept id: fluent-addition-and-subtraction-age-9. Subject: maths. Licence: CC BY-SA 4.0.

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