Finding a missing number in addition

Understand subtraction as finding an unknown addend (e.g. 10 − 8 = ? is the same as 8 + ? = 10)

Usually learned at ages 6–7

Builds on: Addition as combining or putting together two, Subtraction as taking away or separating

Nothing here yet in this language. Add the first explanation with your AI.

On the map from: Marble Skill Taxonomy (v1), © Generative Spark, Inc. (withmarble.com), text CC BY-SA 4.0, database ODbL 1.0: https://github.com/withmarbleapp/os-taxonomy