Evaluating Algebraic Expressions with Substitution Today you will learn to: Use the order of operations to evaluate expressions containing variables. Translate verbal phrases into algebraic expressions. M07. B-E.1.1.1: Apply properties of operations to add, subtract, factor, and expand linear expressions with rational coefficients M07.B-E.2.1.1: Apply properties of operations to calculate with numbers in any form. Warm-up Problem: Variables and Expressions The perimeter of a rectangle can be found using the formula 2l + 2w, where l represents the length and w represents the width. Find the perimeter if l = 6 units and w = 3 units. Evaluate Expressions Algebra is a language of symbols. One symbol that is frequently used is a variable. A variable is a placeholder for any value, and is most commonly represented by letters. An expression like the one above is an algebraic expression because it contains sums and/or products of variables and numbers. Watch the video from Khan Academy.Watch the video from Khan Academy. Evaluate Expressions: Examples Translate Verbal Phrases The first step in translating verbal phrases into algebraic expressions is to choose a variable and quantity for the variable to represent. This is called defining a variable. Phrases that indicate an operation are: Translate Phrases into Expressions: Examples Translate the following verbal phrases into algebraic expressions. You DO NOT evaluate the expressions.