

Multiplication
Division
Addition
Whole numbers
What is a prime number?
A prime number is a whole number with exactly two factors, itself and 1.
Okay, maybe that's a bit hard to understand. Let's take a look at some examples:
The number 5 is a prime number because it cannot be divided evenly by any other numbers except for 5 and 1.
The number 4 is not a prime number because it can be divided evenly by 4, 2, and 1.
Is the number 13 a prime number?
It can't be divided by 2, 3, 4, 5, 6, 7, 8....etc. Only by 1 and 13. Yes, 13 is a prime number.
Is the number 25 a prime number?
It can't be divided by 2, 3, 4....true. Ah, but it can be divided by 5, so it is not a prime number.
Here is a list of the prime numbers between 1 and 100:
2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97
Take a look at a few of them and see if you can figure out any other number that they can be divided by other than the number itself or the number 1. (hint: we promise the answer is "no" and they are, therefore, prime numbers).
Some tricks to prime numbers:
 The number 1 is not considered a prime number.
 All even numbers greater than 2 are not prime numbers.
 There are an infinite number of prime numbers.
 6089
 60899
 608999
 6089999
 60899999
 608999999
The fundamental theorem of arithmetic says that any number can be expressed by a unique product of prime numbers.
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