Math Dictionary / Prime Number
Prime Number
A prime number is a whole number greater than 1 with exactly two factors: 1 and itself.
Number SystemGrade 4Grade 5Grade 6GED
What it means
Prime numbers cannot be divided evenly by other whole numbers.
Also called: prime
Examples
| 2 is prime |
| 7 is prime |
| 9 is not prime because 3 x 3 = 9 |
Common mistake
The number 1 is not prime because it has only one factor.
Try one
Question: Is 11 prime?
Show answer
Yes. Its only factors are 1 and 11.