# What Are Twin Prime Numbers?

An error occurred trying to load this video.

Try refreshing the page, or contact customer support.

Coming up next: What is an Acre? - Definition & Measurement

### You're on a roll. Keep up the good work!

Replay
Your next lesson will play in 10 seconds
• 0:03 Introducing Twin Primes
• 0:31 Prime Numbers
• 1:20 Twin Prime Numbers
• 1:52 Practice
• 2:19 Fun Facts
• 3:06 Lesson Summary
Save Save

Want to watch this again later?

Timeline
Autoplay
Autoplay
Speed Speed

#### Recommended Lessons and Courses for You

Lesson Transcript
Instructor: Mark Boster
There are all kinds of numbers: even, odd, positive, negative, and prime numbers, just to name a few. Did you know that there are even twin prime numbers? In this lesson, you'll learn what twin prime numbers are and some interesting facts about them.

## Introducing Twin Primes

Can you answer this riddle? There were 2 babies born on the same day, in the same hospital, by the same parents, but they were not twins. How did this happen? The answer may surprise you: They were 2 babies from a set of triplets!

You know what a twin is, but do you know what a twin prime number is? In this lesson, we're going to explore twin prime numbers and learn how to identify them. But first, let's quickly review prime numbers.

## Prime Numbers

A prime number is a whole number greater than 1 that only has whole number factors of 1 and itself. When we say that it only has whole number factors of 1 and itself, we mean the only two whole numbers you can multiply to get that number are 1 and the number itself.

For example, if you want to multiply two numbers to get the number 7, the only way to do it is 7 x 1 = 7. Another example of a prime number is 5. The only way to multiply whole numbers to get 5 is 5 x 1 = 5. There's no other way.

The first 9 prime numbers are 2 , 3 , 5 , 7, 11, 13, 17, 19, and 23.

If you do the math, you'll see that the only factors of these prime numbers are 1 and the number itself.

## Twin Prime Numbers

Now that we've refreshed our memory of prime numbers, let's dig into twin prime numbers. Twin prime numbers are two consecutive prime numbers that differ by 2. This is easy to remember when you remember that twins are a set of 2, and twin primes differ by 2.

For example, from our set of 9 prime numbers, there are 4 sets of twin prime numbers: 3 and 5, 5 and 7, 11 and 13, and 17 and 19. The numbers in each of these pairs differs by exactly 2.

To unlock this lesson you must be a Study.com Member.

### Register to view this lesson

Are you a student or a teacher?

#### See for yourself why 30 million people use Study.com

##### Become a Study.com member and start learning now.
Back
What teachers are saying about Study.com

### Earning College Credit

Did you know… We have over 200 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.