An event is any set of outcomes of the experiment. An event is a subset of sample space S. The event is said to
occur if the outcome of the experiment is contained in it.
Union of events: The union of events A and B, denoted by A ∪ B, consists of all outcomes that are in
A or in B or in both A and B. It corresponds to combining descriptions of the two events
using the word “or.”
Shaded region shows A ∪ B
Intersection of events: The intersection of events A and B, denoted by A ∩ B, consists of
all outcomes that are in both A and B. It corresponds to combining
descriptions of the two events using the word “and.”
How do we illustrate the Union and Intersection of events?
Consider a die and a coin are tossed. Let A be the event that a tail comes out and B the
event that a 5 comes out. Illustrate
A
∪
B
and
A
∩
B.
By Listing method
The sample space, S = {H1, H2, H3, H4, H5, H6, T1, T2, T3, T4, T5, T6}
A = {1T, 2T, 3T, 4T, 5T, 6T}
B = {5T, 5H}
A
∪
B
= {1T, 2T, 3T, 4T, 5T, 5H, 6T}
A
∩
B
= {5T}
Shaded region shows A ∩ B
MATHEMATICS 10
Name: Score:
Section: Date:
LEARNING ACTIVITY SHEET
Illustrating Events, the Union and Intersection of Events
I. Background Information for Learners
This activity sheets serve as your self-learning guide. It facilitates lesson comprehension as it
focuses on your mastery on illustrating events, and the union and intersection of events.
Looking back to the knowledge and skills related to sets, counting techniques and probability
of simple events will help you illustrate events, its union and intersection.
Here are some of the concepts that may guide you in illustrating events, its union and
intersection.
