Prime and composite numbers review
Review prime and composite numbers, and try some practice problems.
What are prime numbers?
Prime numbers are numbers with exactly factors.
A prime number's only factors are and the number .
is an example of a prime number. Its only factors are and . It is not evenly divisible by any other whole numbers.
Want to learn more about prime numbers? Check out this video.
Practice set 1: Identifying prime numbers
Which of these numbers is prime?
What are composite numbers?
Composite numbers have more than factors. A composite number has factors in addition to and the number .
is an example of a composite number. The factors of are and All of these numbers divide into evenly.
Want to learn more about recognizing prime and composite numbers? Check out this video.
Want more ways to think about prime and composite numbers? Check out this article.
Practice set 2: Identifying composite numbers
Which of these numbers is composite?
Want to join the conversation?
- How did scientists discover about prime numbers
Edit: that was a weird question….(53 votes)
- I actually have no idea. But I imagine that a mathematician found out that some numbers can only be divided by one and itself. But I am not sure.(35 votes)
- is 2 the only even prime number(24 votes)
- yeah it is the only even prime number(7 votes)
- One question about this: is 1 a prime or a composite number? Neither of those numbers.(17 votes)
- Its a neither because it is cannot be divisible by 2 natural number or it has only on factor(2 votes)
- Is 1 a prime number or a compsite number?(7 votes)
- It is neither prime nor composite because it's only factor is 1.(15 votes)
- Why is 2 the lone even prime number?(6 votes)
- A number is prime only if it can be divided by 1 and itself. Because the only factors of 2 are 1 and 2, 2 matches the definition of a prime number and is, therefore, prime.(15 votes)
- is 349,860,748,398 a composite or prime?(8 votes)
- Composite. It is divisible by other numbers than 2, such as 3.(7 votes)
- whats the point of learning about prime and composites if no one really uses them outside of school?(9 votes)
- In order to learn how to work with fractions, you need to know the difference between prime & composite numbers. Fractions exist in many real life situations outside of school.(9 votes)
- How did prime numbers get the name prime numbers?(9 votes)
- prime means something like "only" or "just one" and prime numbers have no other number they are divisible by but themselves and 1. but all whole numbers are divisible by 1.(5 votes)
- Is 31,21,31,41,51,61,71 and 81 prime numbers?(5 votes)
- All are prime except for 21, 51, and 81 (all of which are divisible by 3).(11 votes)
- Is this important for school and our grade?? I am in 4th.(5 votes)