1. Writing Algebraic Expressions

2. Word phrases can be written as algebraic expressions. Use the words to determine what operation you are using. Use a variable for the phrase “ a number. ”

3. Adding Phrases Plus More than Sum Increased by

4. Subtracting Phrases Minus Difference Subtracted from Decreased by Less than

5. Multiplying Phrases Times Product of Dividing Phrases Quotient Divided by

6. Example: 7 decreased by b “Decreased by” means subtract. 7 - b

7. Example: The product of 19 and k “Product” means multiply. We show multiplication by placing the factor right next to the variable. 19k

8. Less than, more than Some word phrases contain the words “ less than ” or “ more than. ” When you see those words, start with the second part of the phrase. Example: 23 less than m m - 23

9. Example: 32 less than 5 times c The 32 is less than the 5 times c, which means we subtract 32 from the 5 times c. So, start with 5 times c. 5c - 32

10. Describing Unknown Numbers When you don ’ t know what a number is, let a variable stand for that number. Use an algebraic expression to describe what you ’ re looking for.

11. Example Write an algebraic expression to describe Jerry’s age. Use the following information: Jerry is 4 years younger than his brother Steve. First, we have to know how old Steve is. We do not have an age for Steve, so we will use a variable: Let s = Steve’s age. Now that we have determined Steve’s age (s), we can use it to determine Jerry’s age. Jerry is 4 years younger than Steve. s - 4

12. If Steve is 22 years old, then how old is Jerry? s - 4 22 - 4 18 Jerry is 18 years old.