A factor tree starts with one number, such as 8. You draw to lines, and at the end of each is a possible way to divide 8, such as 4 and 2, because 4*2=8. Then, you divide 4 by 2, which is the only possible way without getting a 1 or a 4. Then, since 2 cannot be divided by 2 or 1.That is a complete factor tree. You can tell if a factor tree is over if you end up with a prime number.
