1. 1.1 Subsets of Real Numbers
NO CALCULATOR!!

2. Real Numbers
Real (R ) Rational (Q) Irrational (H) Integers (Z) Whole (W) Natural (N)
Terminating or repeating decimal
{4, –5, 0.02, , }
{…,–2, –1, 0, 1, 2, …}
{0, 1, 2, 3, …}
{1, 2, 3, …}

3. Examples (TWAP) In which sets does each belong?2
5/8 
1.6
0.3333… –7
 N, W, Z, Q, R
 Q, R
 H, R
 Q, R
 Q, R
 Z, Q, R
 H, R

4. Union & Intersection of Sets
Union of Sets: A  B
in A, in B, or in BOTH
include ALL (don’t repeat)
Intersection of Sets: A  B
must be in BOTH A and B
only include the elements
in both sets
looks like a “U”
looks like an “A” (for AND)

5. Examples A = {0, 2, 3, 4, 6, 9} B = {0, 2, 4, 6, 8, 10} C = {3, 4, 5, 6}
C  B
(A  B)  C
all members, but don’t repeat
{0, 2, 3, 4, 6, 8, 9, 10}
include elements that are only in BOTH
{4, 6}
{0, 2, 3, 4, 6, 8, 9, 10}
 {3, 4, 5, 6}
Grouping symbol first!
{3, 4, 6}

6. Examples (TWAP) Let R = {real numbers}, H = {irrational numbers}, Q = {rational numbers}, Z = {integers}, W = {whole numbers}, N = {natural numbers}
Find Z  H
Find Z  Q
3) Find N  Q
4) Find N  H
 (null set) Q Q
 (null set)

7. Homework
# Pg – 9 odd, 11 – 20 all, 21 – 31 odd