- This PDF File - Math Addition and Subtraction within 20 is a foundational math skill where students learn to add and subtract numbers whose answers stay between 0 and 20. Each page will have a theme for a month. It typically includes : - Adding numbers up to a total of 20 - Subtracting numbers from 20 or less - Understanding number relationships and fact families - Using strategies like counting on, counting back, number lines, ten frames, and manipulatives Do you think you're looking for more