# Mentally adding hundreds to 3-digit numbers

Mentally add and subtract a three-digit number and hundreds

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), 10 or 100 More or Less (hard, https://ai.page/c/10-or-100-more-or-less/en.md)

Concept id: mentally-adding-hundreds-to-3-digit-numbers. 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.