National STEM Standards
STEM.M. MATHEMATICS: National Council of Teachers of Mathematics (NCTM)
2.2. Represent and analyze mathematical situations and structures using algebraic symbols.
2.2.3. Express mathematical relationships using equations.
2.3. Use mathematical models to represent and understand quantitative relationships.
2.3.1. Model problem situations with objects and use representations such as graphs, tables, and equations to draw conclusions.