PA.2.1. Numbers, Number Systems and Number Relationships
2.1.4.F. Understand the concepts of addition and subtraction and their inverse relationships; understand the concepts of multiplication and division; use the four basic operations to solve problems, including word problems and equations.
PA.2.8. Algebra and Functions
2.8.4.B. Select and use strategies, including concrete objects, to solve number sentences (equations and inequalities) involving whole numbers or unit fractions and explain the method of solution.