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 ...

Draw two branches from the number to split the number into a pair of factors, greater than 1 Write each factor at the end of each branch. If a factor is a prime number, the branch does not extend ...