Introduction to the Number System
Name:
Period:
Subset: A subset is a set that is part of a larger set.
Example: Set: A box of crayons {yellow, red, orange, blue}
Subset: You pull out two crayons {yellow and red}
Subsets of the Number System
Term
Natural Numbers
Whole Numbers
Integers
Definition
The set of counting numbers
starting at 1 and going on
forever. This set does NOT
include fractions or decimals.
{1 , 2, 3, 4, …}
The set of numbers starting at
0 and going on forever. This
set does NOT include fractions
or decimals.
{0, 1 , 2, 3, 4, …}
The set of whole numbers and
their opposites. This set does
NOT include fractions or
decimals.
{…-4, -3, -2, -1, 0, 1 , 2, 3, 4, …}
Examples
Non-examples
1
0
225
49
-16
3.2
8
2
1
2
0
-13
662

27
3
8.536
25
9
3
4
-17
1.646644666444…
0
-2.8
3
11.2
40
8
2.9568
ALWAYS SIMPLIFY BEFORE DETERMINING WHAT SUBSET A NUMBER BELONGS TO!
Working Together
Examples: For each number given below, identify any name that applies from the following choices:
integers, whole numbers, and natural numbers. If none of the above apply, write NONE.
ALWAYS SIMPLIFY BEFORE DETERMINING WHAT SUBSET A NUMBER BELONGS TO!
30
2
A.
20
B.
D.
0
7
E. -11
C.
F.
-16.3
0
7
Practice: Identify each of the following as natural numbers, whole numbers, and/or integers. Write all
subsets that apply. If none of the above apply, write NONE.
ALWAYS SIMPLIFY BEFORE DETERMINING WHAT SUBSET A NUMBER BELONGS TO!
1.
3
7
2.
30
5
3.
0
4.
9.3
5.
-3
6.
0
1
7.
-5.7
8.

9.
6