Algebra and Functions 1.0 Students use and interpret variables, mathematical symbols, and properties to write and simplify expressions and sentences: 1.1 Use letters, boxes, or other symbols to stand for any number in simple expressions or equations (e.g., demonstrate an understanding and the use of the concept of a variable).      •Substitions of Values for Variables  1.2 Interpret and evaluate mathematical expressions that now use parentheses. 1.3 Use parentheses to indicate which operation to perform first when writing expressions containing more than two terms and different operations. 1.4 Use and interpret formulas (e.g., area = length x width or A = lw) to answer questions about quantities and their relationships.      • Determining the Area of a Rectangle  1.5 Understand that an equation such as y = 3x + 5 is a prescription for determining a second number when a first number is given.    • Exploring Equations and Predicting Points on a Line  2.0 Students know how to manipulate equations: 2.1 Know and understand that equals added to equals are equal.    • Understanding Equality in an Equation  2.2 Know and understand that equals multiplied by equals are equal.