A factor is a number that goes into another. The factors of 10 for example are 1, 2, 5 and 10. Prime numbers are a special set of numbers that only have two factors: themselves and 1. An example ...

A prime number has exactly two factors, itself and one. The first ten prime numbers are \({2}\), \({3}\), \({5}\), \({7}\), \({11}\), \({13}\), \({17}\), \({19 ...