Changes

A '''set''' is a collection of objects.  Sets are the subject of [[set theory]].  Two sets are the same if they contain the same elements, regardless of the order they are in. Sets are written in set notation, such as <math>\{1,2\}</math> indicating the set containing the elements 1 and 2. This is the same as the set <math>\{2,1\}</math> because order does not matter when comparing sets.

A '''set''' is a collection of objects called elements.  Sets are the subject of [[set theory]].  Two sets are the same if they contain the same elements, regardless of the order they are in. Sets are written in set notation, such as <math>\{1,2\}</math> indicating the set containing the elements 1 and 2. This is the same as the set <math>\{2,1\}</math> because order does not matter when comparing sets.

Also, repetition of elements is irrelevant, so the set <math>\{1,2,2\}</math> is the same as the set <math>\{1,2\}</math>.

Also, repetition of elements is irrelevant, so the set <math>\{1,2,2\}</math> is the same as the set <math>\{1,2\}</math>.