Pennsylvania Core and Academic Standards
PA.CC.2.1.2. Numbers and Operations
CC.2.1.2.B. Numbers & Operations in Base Ten
CC.2.1.2.B.3. Use place-value understanding and properties of operations to add and subtract within 1000.
PA.CC.2.2.2. Algebraic Concepts
CC.2.2.2.A. Operations and Algebraic Thinking
CC.2.2.2.A.1. Represent and solve problems involving addition and subtraction within 100.
CC.2.2.2.A.2. Use mental strategies to add and subtract within 20.