Objective
The student will be able to:
divide rational numbers.
SOL: none
Designed by Skip Tyler, Varina High School and Nicole Kessinger, Deep Run High School
Dividing Rules
1) If the numbers have the same
signs then the quotient is positive.
-32 ÷ (-8 )= 4
2) If the numbers have different
signs then the quotient is negative.
81 ÷ (-9) = -9
When dividing two negative
numbers, the quotient is positive.
1. True
2. False
Answer Now
When dividing a negative number and
a positive number, use the sign of the
larger number.
1. True
2. False
Answer Now
a
b
The reciprocal of
is
b
a
where a and b  0.
The reciprocal of a number is called its
multiplicative inverse.
A number multiplied by its
reciprocal/multiplicative inverse is
ALWAYS equal to 1.
Example #1
7
2
The reciprocal of
is
.
7
2
2 7
1
 
1
7 2
1
Example #2

1
The reciprocal of -3 is  .
3
1
3
1
1

3

1
1
Basically, you are flipping the fraction!
We will use the multiplicative inverses
for dividing fractions.
Which statement is false about
reciprocals?
1.
2.
3.
4.
Reciprocals are also called
additive inverses
A number and its reciprocal
have same signs
If you flip a number, you get
the reciprocal
The product of a number and
its reciprocal is 1
Answer Now
Examples
1)  3  5
4
8
When dividing fractions, change
division to multiplying by the reciprocal.
3
8
24



20
4
5
6

5
3 
2)  1  
 
5
 10 
1  10 

 

5  3 
10

15
2

3
1.
2.
3.
4.
18
-18
7
-7
What is the quotient of
-21 ÷ -3?
Answer Now
1 10

?
5
3
1.
2.
3.
4.
2
3
2
3
3
50
3
50 Answer Now
.
.
.
.