1. Algebraic Expressions
An algebraic expression uses a letter, or variable, to stand for one or more unknown numbers. Mathematical symbols are often used to translate word phrases into algebraic expressions.

2. Algebraic Expressions
Certain word phrases are associated with each
operation.
+….Sum of, increased by, more than
-…..Difference of, decreased by, less than
X….Product of, multiplied by, twice
/.…Quotient of, divided by, ratio

3. Algebraic Expressions
Let n represent the number:
Example 1: 6 more than twice a number
2 x n or 2n + 6
Example 2: less than half a number
1 x n – 18 or 1n – 18

4. Translate an Algebraic Expression
Write a word phrase for the algebraic expression.
A. 3(n – 5) 3 times the difference of
a number minus 5
B. R + 8 The sum of a number and
divided by 3

5. Evaluating Expressions and Formulas
To evaluate an expression, first replace the variable by a given value. Then simplify.
Ex. 1 Evaluate 4x + 7 for x = 5
Step 1: Replace x with 5
4(5) + 7
Step 2: Simplify
= 27

6. Evaluating Expressions and Formulas
Sometimes there is more than one variable in an expression.
Example 2: Evaluate 2a + b for a = 2, b = 5 and
c = c
Step 1: Replace a with 2, b with 5 and
c with 3
2 x 3
Step 2: Simplify = 9 = 3

7. Practice Exercises 1. Take out a sheet of paper and number 1-20
2. Write your name, date, and # on the right
hand side of paper.
Complete all 20 problems.
4. If you have questions, please come to me
one at a time.
Homework: Translating Algebraic Expressions Worksheet