Common
Divisors &
GCD

What is the free Common Divisors & GCD Quiz?

Common Divisors & GCD Quiz is a free four-choice quiz app where you practice common divisors and the greatest common divisor.

You answer questions such as "Which number is a common divisor of 12 and 18?" and "What is the greatest common divisor of 12 and 18?" in a time-attack style.

Review common divisors and GCD

A common divisor is a number that divides two numbers evenly. For example, the common divisors of 12 and 18 are 1, 2, 3, and 6.

The greatest common divisor, or GCD, is the largest common divisor. For 12 and 18, the GCD is 6.

Common divisor and GCD courses

1. Common Divisor Beginner 10-question course

Start with small numbers and practice choosing a common divisor.

2. Common Divisor Intermediate 20-question course

Practice a little longer with larger number pairs.

3. Common Divisor Advanced 30-question course

Train speed and accuracy with more varied common divisor questions.

4. Common Divisor Endurance 50-question course

Challenge 50 common divisor questions and aim to finish with a high score.

5. GCD Beginner 15-question course

Practice finding the greatest common divisor with beginner-level number pairs.

6. GCD Intermediate 25-question course

Build speed with 25 greatest common divisor questions.

7. GCD Advanced 35-question course

Work through more varied GCD questions for stronger accuracy.

8. GCD Endurance 55-question course

Take on 55 greatest common divisor questions in endurance mode.

Ranking and learning records

All courses support ranking by correct answers and clear time. MyPage also lets you review your play history, best records, and often missed questions.

For students, review, and brain training

The simple 4-choice format is useful for elementary school students learning factors, for adults reviewing math, and for quick brain training.

Thank you for using Common Divisors & GCD Quiz.