WA.4.4. Additional Key Content (Geometry/Measurement, Algebra, Data/Statistics/Probability) Students use coordinate grids to connect numbers to basic ideas in algebra and geometry. This connection between algebra and geometry runs throughout advanced mathematics and allows students to use tools from one branch of mathematics to solve problems related to another branch. Students also extend and reinforce their work with whole numbers and fractions to describe sets of data and find simple probabilities. Students combine measurement work with their developing ideas about multiplication and division as they do basic measurement conversions. They begin to use algebraic notation while solving problems in preparation for formalizing algebraic thinking in later grades.
4.4.A. Represent an unknown quantity in simple expressions, equations, and inequalities using letters, boxes, and other symbols.