1. 4 WARM UP NUMERICAL EXPRESSIONS Evaluate the expression (Lesson 1.3)
9 – 2 ● 2 – 3
1 ● ● 5
– 7
4 ●

2. 3 WARM UP NUMERICAL EXPRESSIONS Evaluate the expression (Lesson 1.3)
9 – 2 ● 2 – 3
1 ● ● 5
– 7
4 ●

3. 2 WARM UP NUMERICAL EXPRESSIONS Evaluate the expression (Lesson 1.3)
9 – 2 ● 2 – 3
1 ● ● 5
– 7
4 ●

4. 1 WARM UP NUMERICAL EXPRESSIONS Evaluate the expression (Lesson 1.3)
9 – 2 ● 2 – 3
1 ● ● 5
– 7
4 ●

5. WARM UP NUMERICAL EXPRESSIONS Evaluate the expression (Lesson 1.3)
NUMERICAL EXPRESSIONS Evaluate the expression (Lesson 1.3)
9 – 2 ● 2 – 3
1 ● ● 5
– 7
4 ●

6. 9/27/2012 2.5 Multiplying Real Numbers
Goal: Multiply real numbers using the rule for the sign of a product.
Key Words:
Closure property, commutative property, associative property, identity property, property of zero, property of negative one.

7. Multiplying Real Numbers
The product of any two numbers is itself a unique real number. We say that the real numbers are closed under multiplication. This fact is called the closure property of real number multiplication. Multiplication by a positive integer can be modeled as repeated addition.
EXAMPLE:
3(-2) =
(-2) + (-2) + (-2) = -6
This suggests that the product of a positive number and a negative number is NEGATIVE

8. Multiplying Real Numbers
-3(-2) =
-(3)(-2) =
- (-6) = 6
This suggests that the product of two negative numbers is POSITIVE.

9. Multiplying Real Numbers
RULES FOR THE SIGN OF A PRODUCT OF NONZERO NUMBERS
A product is negative if it has an odd number of negative factors.
EXAMPLES:
-4(5) = (-3) = -6 4(-1)(2) = -8
A product is positive if it has an even number of negative factors
EXAMPLES:
-4(-5) = (-3) = 6 -4(-1)(2) = 8

10. Multiplying Real Numbers
RULES FOR THE SIGN OF A PRODUCT OF NONZERO NUMBERS
A product is NEGATIVE if it has an odd number of negative factors.
A product is POSITIVE if it has an even number of negative factors.

11. Multiplying Real Numbers
3(-5)
-2(4)(5)
9(-1)

12. Multiplying Real Numbers
9(-1)
-5(7)
-4(-6)

13. YOUR TURN ASSIGNMENT: WORKBOOK Page 37 #s 1-6 TEXT BOOK
Page 96 #s and