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The numbers we've examined so far have been fairly simple to factor. Now let's look at a general method for finding prime factors. Note 4
One method is to draw a factor tree. To do this, write a number -- 24, for example -- and then draw an upside-down V under it. This V represents two "branches" of the factor tree. Think of a pair of numbers with the product 24; for example, 4 and 6. Check to see if either of these numbers is prime. In this case, the answer is no.
Draw another V under each number that is not prime, and find two factors for each of these numbers. In this case, we will find the factors 2 and 2 for 4, and 2 and 3 for 6. Now we have four factors, 2, 2, 2, and 3, all of which are prime numbers. This is the prime factorization of 24.
In mathematics, we like to do things via consistent algorithms. So rather than just picking two factors, it's a good idea to make the process more consistent by first finding the smallest prime factor and its partner and then repeating that process on the partner (since the first number is guaranteed to be prime). For example, you could factor out all of the possible 2s, then all the 3s, then 5s, 7s, and so on, until the number is completely factored. Here is what the diagrams look like for the numbers 24 and 36:
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1) can be factored into a product of prime numbers and that this product is unique except for the order of the factors. This is another reason why 1 cannot be considered prime -- otherwise, this, and every other result that builds on it, falls apart.
