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Set operations

How to describe and combine sets: membership and subsets, union, intersection and complement, set-builder notation, and splitting a set into parts.

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8

lessons

88

practice questions

1

prerequisite lesson

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2 of the 8 lessons here are free to preview - the whole explanation and worked example, with no account and no email.

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Lesson 05 · Set union and intersection

U
A
B
A only
A∩B
B only
Neither A nor B

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The 8 lessons

The 8 lessons in this unit. Expand any one to see what it covers. Each unlocks when its own prerequisites are passed.

01

Sets and elements

12 questions

Learn what sets are, how to list their elements using curly brace notation, use membership symbols ∈\in and ∉\notin, and recognise the empty set ∅\emptyset.

Covers

What is a set

Element membership

The empty set

02

Number sets and notation

12 questions

Learn the standard number sets N\mathbb{N}, Z\mathbb{Z}, Q\mathbb{Q}, and R\mathbb{R}, understand their containment relationships, and use superscript notation for restricted sets like Z+\mathbb{Z}^+.

Covers

Natural numbers and integers

Rational and real numbers

Restricted number sets

03

Set-builder notation

12 questions

Learn to read and write set-builder notation {x:condition}\{x : \text{condition}\} to describe sets by a rule rather than listing elements, and specify domains using {x∈S:condition}\{x \in S : \text{condition}\}.

Covers

Reading set builder notation

Writing set builder notation

Specifying the domain

04

Subsets and cardinality

12 questions

Learn subset notation ⊆\subseteq and ⊂\subset, prove set equality by showing mutual containment, and compute cardinality ∣A∣|A| for finite sets.

Covers

Subsets

Set equality

Cardinality

05

Set union and intersection

Preview

12 questions

Learn how to combine sets using union and intersection operations and visualise these relationships using Venn diagrams.

Covers

Set union

Set intersection

Venn diagrams

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06

Set complements

Preview

12 questions

Learn to compute the complement of a set, apply key properties like double complementation, and use De Morgan's laws to relate complements to unions and intersections.

Covers

The complement

Properties of complements

De Morgan's laws

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07

Set difference

8 questions

Learn how to find the set difference of two sets, the elements of one set that are not in another, and rewrite it as an intersection with a complement, including when the sets are built from unions.

Covers

The set difference A∖BA \setminus B

Difference as an intersection

08

Partitions

8 questions

Learn to identify when a collection of sets forms a partition of a universal set - pairwise disjoint and exhaustive - and recognise common partitions including the complement partition {A,Ac}\{A, A^c\}.

Covers

What is a partition

Common partitions

Where this unit sits in the curriculum

This unit is part of our Mathematical Foundations for ML learning path, which contains 97 lessons. Every one of them is drawn below.

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Every dot is a lesson and every line a prerequisite. The 8 red dots are the lessons in Set operations; the 1 blue dots feeding into them are the lessons Set operations depends on; the 88 pale dots are the rest of the learning path, which come after Set operations or alongside it.Set operationsFirst lessons on the left97 lessons

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8 lessons in this unit

1 prerequisite lesson across the unit, counting every step back to the start

88 other lessons in the learning path - after this unit, or alongside it

Every dot is a lesson, every line a prerequisite. You can only start a lesson once you have mastered all of its prerequisites, so you are always building on solid foundations.

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