# Mental addition and subtraction (age 7+)

Mentally add and subtract a three-digit number and ones

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 (soft, https://ai.page/c/fluent-adding-and-subtracting-within-100/en.md)

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

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