K.OA. Kindergarten - Operations and Algebraic Thinking
K.OA.A. Understand addition as putting together and adding to, and understand subtraction as taking apart and taking from.
K.OA.A.1. Represent addition and subtraction with objects, fingers, mental images, drawingsDrawings need not show details, but should show the mathematics in the problem. (This applies wherever drawings are mentioned in the Standards.), sounds (e.g., claps), acting out situations, verbal explanations, expressions, or equations.
K.OA.A.3. Decompose numbers less than or equal to 10 into pairs in more than one way, e.g., by using objects or drawings, and record each decomposition by a drawing or equation (e.g., $5 = 2 + 3$ and $5 = 4 + 1$).