1. Variables and Expressions

2. Variables and Expressions: Definitions
Variable – letter that represents a value that can change. Ex: x
Algebraic expression - contains variables; different from an equation because there is no equal sign. Ex: x + 7; non-example: x+7 = 9
Evaluate - to find it’s value. Ex: Evaluate x +7 when x = 2 → = 9.

3. Key Words and Phrases for Translating Between Expressions and Words
Addition +
Subtraction -
Multiplication x
Division ÷
Plus
Minus
Times
Divided by
Sum
Difference
Product
Quotient
Increased by
Less than
Equal groups of
Separate into equal groups
Put together
Find how much more
Combined
Find how much less
The quantity of

4. Translating Between Words and Algebra
Example 1: x + 3
The sum of x and 3
X increased by 3
Example 2: m – 7
The difference of m and 7
7 less than m

5. Example 3: 2 · y
2 times y
The product of 2 and y
Example 4: k ÷ 5
K divided by 5
The quotient of k and 5

6. Example 5:
Eva reads 25 pages per hour.
25 · h
25h

7. Evaluating Algebraic Expressions
Examples 6 – 8 Directions: Evaluate each expression for x = 8, y = 5, and z = 4.
Example 6: x + y Example 7: 𝑥 𝑧 Example 8: yz
X + y = = y · z = 5 · 4
= = 2 = 20