3-5 Working With Sets

Objectives

To write sets and identify subsets

To find the complement of a set

Image Long Description

Recall from Lesson 1-3 that a set is a collection of distinct elements. A subset contains elements from a set. For example, the number 6 on the telephone keypad corresponds to the set {M, N, O}. The set {M, O} is one subset of this set.

Essential Understanding Sets are the basis of mathematical language. You can write sets in different ways and form smaller sets of elements from a larger set. You can also describe the elements that are not in a given set.

Roster form is one way to write sets. Roster form lists the elements of a set within braces, {}. For example, you write the set containing 1 and 2 as {1, 2}, and you write the set of multiples of 2 as {2, 4, 6, 8, …}.

Set-builder notation is another way to write sets. It describes the properties an element must have to be included in a set. For example, you can write the set {2, 4, 6, 8, …} in set-builder notation as {x | x is a multiple of 2}. You read this as “the set of all real numbers x, such that x is a multiple of 2.”

Problem 1 Using Roster Form and Set-Builder Notation

Plan

How are roster form and set-builder notation different?

Roster form lists the elements of a set. Set-builder notation describes the properties of those elements.

How do you write “T is the set of natural numbers that are less than 6” in roster form? In set-builder notation?

Roster form	Set-builder notation

Table of Contents