1. Section 1.1 Variables and Expressions
Algebra Concepts
Section 1.1
Variables and Expressions

2. Cartoon of the day!

3. Candy bars cost 75 cents.
How many candy bars can you buy for $3.00?
How many candy bars can you buy for $9.00?

4. 3.00/.75 = 4 candy bars
9.00/.75 = 12 candy bars
3.00/.75 is a numerical expression
When the price of a candy bar is unknown, a variable can be used.

5. Any letter can be used for a variable
Let’s use p for the price of a candy bar.
3.00/p would represent how many candy bars we could buy with $3.00.
3.00/p is an algebraic expression

6. What’s the difference between a numerical expression and an algebraic expression?

7. A numerical expression has only numbers while an algebraic expression includes a variable.

8. Writing an algebraic expression
Key words that translate into a plus sign (+):
Total
More than
Increased by

9. Key words that translate into a minus (-) sign:
difference
fewer than
less than
decreased by

10. Keys words that translate into a multiplication ×, ∙ or ( )( ) symbol.
product
times

11. Key words that translate into a division ÷ or − symbol.
quotient
divided by

12. Write an algebraic expression for
‘Two times a number increased by 5’

13. 2n +5 is the algebraic expression.
Any letter can be used

14. Watch order in algebraic expressions with a subtraction symbol
Order is important!!!!!!!
Write an algebraic expression for:
‘10 less than a number’

15. The answer is n − 10
‘A number decreased by 10’ would also be n − 10
What would the order be for ’10 fewer than a number’?