Practice Definition Of Countable Sets (3.3) - Countable and Uncountable Sets
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Definition of Countable Sets

Practice - Definition of Countable Sets

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Practice Questions

Test your understanding with targeted questions

Question 1 Easy

Define a countable set.

💡 Hint: Think about the characteristics of finite sets.

Question 2 Easy

Is the set of prime numbers countable?

💡 Hint: Can you list them in order?

4 more questions available

Interactive Quizzes

Quick quizzes to reinforce your learning

Question 1

What defines a countable set?

It must have a finite number of elements.
It can be either finite or have the same cardinality as positive integers.
It cannot have an infinite number of elements.

💡 Hint: Remember the definition of countability.

Question 2

Which set is not countable?

The set of natural numbers.
The set of real numbers.
The set of odd numbers.

💡 Hint: Think about how many numbers are between any two integers.

1 more question available

Challenge Problems

Push your limits with advanced challenges

Challenge 1 Hard

Determine if the set of all even integers is countable and justify your answer.

💡 Hint: Consider the way they pair with positive integers.

Challenge 2 Hard

Show whether the set of all subsets of natural numbers is countable.

💡 Hint: Think about how many subsets can exist versus elements.

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