A number may be made by multiplying two or more other numbers together. The numbers that are multiplied together are called factors of the final number.
All numbers have a factor of one since one multiplied by any number equals that number.
All numbers can be divided by themselves to produce the number one. Therefore, we normally ignore one and the number itself as useful factors. A Prime number has only itelf and one as factors. A composite number has factors other than 1 and itself. All of the other numbers betwen 4 and 100 are composite.