1. 1.1 Variables and Equations Objective: To simplify numerical expressions and evaluate algebraic expressions. Warm – up:

2. 1.1 Variables and Equations This summer you went to a go-kart track. Each race cost $5.25. – Fill in the following chart. Number of Races Cost to Race 1 2 3 4 Could we rewrite the cost of racing as an expression? – How? – What do we need? A variable is a symbol used to represent one or more numbers. The numbers are called values of the variable.

3. 1.1 Variables and Equations The variable expression for the race track would be ____________. An example of a numerical expression, or numeral, would be _________. – This names the variable expression with a particular number in place. The number named by the numerical expression is called the value of the expression. – Using the example from before, __________ is the value of the expression. To show to two expressions have the same value, what sign is used? _________

4. 1.1 Variables and Equations The equals sign (=) is the most common way to say “write something in its simplest form”. For example: Likewise, replacing a numerical expression by the simplest name for its value is called simplifying the expression. (PEMDAS)

5. 1.1 Variables and Equations When a variable expression is turned into a numerical expression to be simplified, the Substitution Principle is used. Substitution Principle: An expression may be replaced by another expression that has the same value. Example: Let x = 3 and y = 4. Evaluate:

6. 1.1 Variables and Equations What is the difference between simplifying and evaluating? Homework: – Pg. 3 Written Exercises #1 – 39 odd