1. Variables and Expressions
Definitions:
1) Variable – a symbol used to represent
a number.
2) Expression - consists of one or more
numbers or variables
along with one or more
operations.

2. Key Words to look for in word problems:
Add Subtract Multiply Divide

3. Example 1: Write as an expression.
A) The sum of k and 20
B) Four times y
C) n divided by 14

4. Example 2: Write a statement for the
expression.
3 + x
y – 12
5n

5. Evaluate the expression.
Use x = 4, y = 5, z = 8
• 4x
• 10 – y
• 3.2z