1-1 Variables & Expressions Objective The student will be able to:

1. 1-1 Variables & ExpressionsObjectiveThe student will be able to: translate verbal expressions into math expressions and vice versa.

2. What is the area of a rectangle? Length times Width If the length is 3 meters and the width is 2 meters, what is the area? A = L x WA = 3 x 2 = 6 meters2 A, L and W are the variables. It is any letter that represents an unknown number.

3. An algebraic expressioncontains: 1) one or more numbers or variables, and 2) one or more arithmetic operations. Examples: x - 3 3 • 2n

4. In expressions, there are many different ways to write multiplication. • 1) ab • 2) a • b • 3) a(b) or (a)b • 4) (a)(b) • 5) a x b We are not going to use the multiplication symbol any more. Why?

5. Division, on the other hand, is written as: 1) 2) x ÷ 3

6. Throughout this year, you will hear many words that mean addition, subtraction, multiplication, and division. Complete the table with as many as you know.

7. Here are some phrases you may have listed. The terms with * are ones that are often used.

8. Write an algebraic expression for1) m increased by 5. m + 5 2) 7 times the product of x and t. 7xt or 7(x)(t) or 7 • x • t

9. 3) 11 less than 4 times a number. 4n - 11 4) two more than 6 times a number. 6n + 2 5) the quotient of a number and 12.

10. Answer Now Which of the following expressions represents 7 times a number decreased by 13? • 7x + 13 • 7x - 13 • 13 - 7x • 13 + 7x

11. Answer Now Which one of the following expressions represents 28 less than three times a number? • 28 - 3x • 3x - 28 • 28 + 3x • 3x + 28

12. 2) Write a verbal expression for: 1) 8 + a. The sum of 8 and a The ratio of m to r Do you have a different way of writing these?

13. Answer Now Which of the following verbal expressions represents 2x + 9? • 9 increased by twice a number • a number increased by nine • twice a number decreased by 9 • 9 less than twice a number

14. Answer Now Which of the following expressions represents the sum of 16 and five times a number? • 5x - 16 • 16x + 5 • 16 + 5x • 16 - 5x

15. When looking at the expression 103, 10 is called the base and 3 is called the exponentor power. 103 means 10 • 10 • 10 103 = 1000

16. How is it said?21 Two to the first power 22 Two to the second power or two squared 23 Two to the third power or two cubed 2n7 Two times n to the seventh power

17. Answer Now Which of the following verbal expressions represents x2 + 2x? • the sum of a number squared and twice a number • the sum of a number and twice the number • twice a number less than the number squared • the sum of a number and twice the number squared

18. Answer Now Which of the following expressions represents four less than the cube of a number? • 4 – x3 • 4 – 3x • 3x – 4 • x3 – 4

19. Evaluate.21 2 22 2 • 2 = 4 23 2 • 2 • 2 = 8 2n7 We can’t evaluate because we don’t know what n equals to!!

20. Is 35 the same as 53?Evaluate each and find out! 35 = 3 • 3 • 3 • 3 • 3 = 243 53 = 5 • 5 • 5 = 125 243 ≠ 125 They are not the same!

21. 1-1 Homework • Pg 9-10 #16-22, 30-40 evens only