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Perfect Numbers
Designed by
The Countesses
Jill, Kathy, Bev, Karen & Sarah
Perfect Numbers
In this presentation you will learn what
perfect numbers are and how to identify
them. You will look at whole numbers,
fractions, and negative numbers.
Definition
A Perfect Number is a number
that has
equal factors.
Examples of perfect numbers
4 = 2x2
25 = 5x5
1= 1x1
64 = 8x8
81 = 9x9
36 = 6x6
The numbers in black are all perfect squares
because they have 2 equal factors.
More Examples
of Perfect Numbers
8 = 2x2x2
1000 = 10x10x10
125 = 5x5x5
The numbers in black are perfect cubes
because they have 3 equal factors.
TRY THESE !!!
Three of the following numbers are perfect squares. Two of
the following numbers are perfect cubes? Find both of the
perfect cubes before you go on.
27
125
144
49
No
This is a Perfect Square.
This number has
two equal factors.
Return
Yes
This is a Perfect Cube.
This number has
three equal factors.
Factor

A factor is a number that divides into
another with no remainder.

2 is a factor of 6 because:


2 divides into 6 three times with no remainder
2 is not a factor of 7 because:

2 divides into 7 three times with a remainder of
one
Special numbers
In addition to whole numbers, you will look
at fractions and negative numbers. The
Rule for perfect numbers still applies to
fractions and negative numbers.
Remember – Numbers can be
perfect squares or perfect
cubes.
Remember !!!
A Perfect Number is a number that
has
equal factors.
Fractions that
are perfect numbers
If both the numerator and denominator are
perfect squares or if both are perfect cubes,
then the fraction is perfect.
¼=½x½
9/25 = 3/5 x 3/5
8/27 = 2/3 x 2/3 x 2/3
3/25 is not perfect because 3 is not perfect.
4/27 is not perfect because 4 is a perfect
square and 27 is a perfect cube.
Which two fractions are
perfect?
9/25
16/21
23
1/36
25
8/25
Good Job !!!
This number is
Perfect.
Return
Sorry
This number is not
Perfect.
Back to the quiz
Review the Rules
Remember !!
A Perfect Number is a number that
has equal factors.
Note: If both the numerator and denominator
are perfect squares or if both are perfect cubes,
then the fraction is perfect.
Negative Numbers
that are Perfect
Perfect cubes can be negative.
-8 is perfect because -8 = -2 x -2 x -2
Perfect squares cannot be negative.
-4 is not perfect because -4 does not
have two equal factors.
(-2 x -2  -4 and 2 x 2  -4)
Which two are perfect?
-25
-1000
-27
-16
Good Job !!!
This number is
Perfect.
Return
Sorry
This number is not
Perfect.
Back to the quiz
Review the Rules
Remember !!
A Perfect Number is a number that
has equal factors.
Perfect cubes can be negative.
Perfect squares cannot be negative.
Final Quiz
11
Click on numbers that are
perfect. ( There are 6.)
17
-9
49/81
- 8/27
100
1/7
End
Good job!!
This number is
Perfect!!!
Find
More
Sorry
This number is
Not Perfect!!
TRY AGAIN