Practice Countably Finite Sets And Countably Infinite Sets (3.4) - Countable and Uncountable Sets
Students

Academic Programs

AI-powered learning for grades 8-12, aligned with major curricula

Professional

Professional Courses

Industry-relevant training in Business, Technology, and Design

Games

Interactive Games

Fun games to boost memory, math, typing, and English skills

Countably Finite Sets and Countably Infinite Sets

Practice - Countably Finite Sets and Countably Infinite Sets

Enroll to start learning

You’ve not yet enrolled in this course. Please enroll for free to listen to audio lessons, classroom podcasts and take practice test.

Learning

Practice Questions

Test your understanding with targeted questions

Question 1 Easy

Define a countably finite set.

💡 Hint: Think about a set you can count entirely—like a box of candies.

Question 2 Easy

Is the set of all even numbers countable?

💡 Hint: Consider how you can list them.

4 more questions available

Interactive Quizzes

Quick quizzes to reinforce your learning

Question 1

Which of the following is a countably finite set?

Set of all positive integers
Set of continents
Set of all real numbers

💡 Hint: Think of how many continents exist.

Question 2

True or False: The set of all prime numbers is uncountable.

True
False

💡 Hint: Recall that primes can be listed as 2, 3, 5, 7, ...

1 more question available

Challenge Problems

Push your limits with advanced challenges

Challenge 1 Hard

Prove that the set of all even integers is countably infinite.

💡 Hint: Show that every positive integer has a unique even counterpart.

Challenge 2 Hard

Explain Cantor’s diagonal argument and how it demonstrates that the reals are uncountable.

💡 Hint: Focus on the construction of a new number that differs from any given entry in the list.

Get performance evaluation

Reference links

Supplementary resources to enhance your learning experience.