1. Review
Add Matrices
Subtract Matrices

2. Objective: students will demonstrate they can apply the rules of multiplication to numerical and algebraic expressions
2.5 Multiplying Numbers

3. Multiplying Integers Multiplication Rules: Number x 0 = 0
Pos. x Pos. = Pos.
Ex: 3 x 4 =12
Neg. x Neg. = Pos.
-4 x -5 = 20
Neg. x Pos. = Neg.
-4 x 8 = -32
Number x 0 = 0
Ex: 8 x 0 = 0
Number x 1 = number
Ex: 9 x 1 = 9

4. Multiplication Properties
Commutative Prop. of Multiplication
AB = BA
2(4) = 4(2)
Associative Prop. of Multiplication
(AB)C = A(BC)
(2 x 1) x 4 = 2 x (1 x 4)

5. Identity Properties Multiplication Property of zero
Property of opposites
a + -1 = -a
= -7
Identity Property of Multiplication
a x 1 = a
7 x 1 = 7
Multiplication Property of zero
a x 0 = 0
6 x 0 = 0

6. Identify the Property Used-t/s
-8 x 0 = 0
2 (-49) = (-49)2
y2 x -1 = -y2
2(pq) = (2p) q
3 (xy) = (3x) y
-8 x 0 = 0
2x3 = 3x2
8 x 1 = 8

7. Teacher Examples
7 x -6
-11 x -9
-8 x -7
9 x 3

8. Student Examples 10 x -11 -6 x -9 -11 x -8 -7 x 4 0 x 60 -6 x -8

9. Multiplying with variables
NOTE: same base add exponents! 3x(2y) 3x(5)6x
-5h(6h) 4(-3n)

10. Multiplying with Variables -st
8j(-2) 3(x)2x -2(-8x)
9a(-2b)a 4x(2x) -3x(2y)4z

11. Story Problems
ELEVATORS An elevator takes passengers from the ground floor down to an underground parking garage. Where will the elevator be in relation to the ground floor after 7 seconds if it travels at a rate of 5 feet per second?
TEMPERATURE The temperature dropped 5°F every hour for the last 10 hours. What is the total change in temperature?

12. Wrap up
Questions/Comments
Hw: text pg. 96, #’s: evens, 62