1. Do Now 9/18/12 Take out HW from last night. Copy HW in your planner.
Text p. 17, #1-4
Copy HW in your planner.
Text p. 20, #10-36 evens, #40 & 41
POTW#1
In your journal section, list as many examples that you can of quantities (numbers in real-life) that change. Then make a second list of quantities that never change. Use examples from your own life.

2. Homework Text p. 17, #1-4 all 1). 3 x 2 = 6 hours
2). 18 ÷ 3 = 6 students
3). 48 ÷ 4 = 12 percussion instruments
4). 7 x 4 = 28 students

3. Objective
SWBAT evaluate variable expressions.

4. Section 1.3, “Variables and Algebraic Expressions”
a letter used to represent one or more numbers. a y e t k s m

5. Constant
a number in an expression that does not change.

6. Algebraic expression
consists of one or more variables, operations, and constants.
e ÷ 6
y – 7
9 + a
3t + 2y
2k - 7 3m

7. To EVALUATE A VARIABLE EXPRESSION-
substitute a number for each variable, perform the operations and simplify, if necessary.
13· n
Substitute 3 for n.
13· 3
Multiply. 39

8. Evaluate the Expression
PEMDAS
4(3) + 2
Substitute
12 + 2 14

9. Evaluate the Expression
x = 3 and y = 4 3
+ 2y
PEMDAS x 3
+ 2(4)
Substitute 3 9

10. Evaluate the Expression
4(x + y)
x = 3 and y = 5
PEMDAS
4(3 + 5)
Substitute
4(8) 32

11. Evaluate the Expression
3(x + y)
x = 2 and y = 5
PEMDAS
3(2 + 5)
Substitute
3(7)
3(49)
147

12. Evaluate the Expression
x = 2 and y = 5 6y
PEMDAS
Grouping symbol
12 – x
Substitute
(6 · 5) ÷ (12 – 2)
30 ÷ 10 3

13. Evaluate the Expression
[w(x + z)] + y
w = 3, x = 4,
y = 2, & z = 6
[3 · (4 + 6)] + 2
PEMDAS
[3 · 10] + 2
30 + 2
30 + 8 38

14. Evaluate the Expression
5x + z
x = 4, z = 6
5(4) + 6
PEMDAS
5 ·
80 + 6 86

15. 24
Homework
Text p. 20, #10-36 evens, #40 & 41