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Section 1.7: Multiplying & Dividing Real Numbers
Intro:
222 
 2   2   2 
  2   2   2 
Multiplying Real Numbers:
1. The product of two numbers with the same sign is ______________.
2. The product of two numbers with different signs is ______________.
Example 1: Multiply.
a.
 6 4
b. 5   10 
c. 2  1
RULE: For any number x, x  0  0 .
Decimals & Fractions follow the same rules:
a.
 4
b.     20 
 5
 1.2 0.05
Be careful with exponents! The exponent only applies to the expression its touching:
a.
 2 
3
b.
 3 
2
c. 23
d. 32
Reciprocal or Multiplicative Inverse:
Two numbers whose product is 1 are called ____________ or ________________ ___________ of each other.
*0 does NOT have a reciprocal.
Example 2: Find the reciprocals.
a. 22
b.
3
16
c. 10
d. 1
Dividing Real Numbers:
1. The quotient of two numbers with the same sign is a ________________ number.
2. The quotient of two numbers with different signs is a ________________ number.
Example 3: Divide.
a.
24
4
RULE: For a  0 ,
b.
36
3
c.
0
a
 0 and
is undefined.
a
0
Example 4: Simplify:
 12  3  3
7   2 
Example 5: Evaluate for x = -2 and y = -4.
a. 5x  y
b.
3x
2y
2  5
 
3  4
3
d.   9
2