Which Of These Is Prime? 4,10,3

A prime number is one that can only be divided by the number one and itself; dividing by any other number would result in a decimal or a fraction.  So think about which numbers 4, 10, and 3 are divisible by:

4 can be divided by 1, 2, and 4:

4/1 = 4
4/2 = 2
4/4 = 1

Because 4 can be divided by another number besides 1 and 4, it is not a prime number.

10 can be divided by 1, 2, 5, and 10:

10/1 = 10
10/2 = 5
10/5 = 2
10/10 = 1

Because 10 can be divided by another number besides 1 and 10, it is not a prime number.

3 can be divided by 1 and 3:

3/1 = 3
3/3 = 1

Because 3 can't be divided by any other numbers besides 1 and 3, it is a prime number.

So of 4, 10, and 3, 3 is the prime number.