All composite numbers can be expressed as unique products of prime numbers. This is accomplished by dividing the original number and its factors by prime numbers until all the factors are prime. A factor tree can help you visualize this.
Example: 210
210 Divide by two.
105,2 Divide by three.
35,3,2 Divide by five.
7,5,3,2 Stop. All the factors are prime.
2 x 3 x 5 x 7 = 210
That's the prime factorization of 210.
The purpose of a factor tree is to notate the process of finding the prime factorization. If a number is already prime, a factor tree is not necessary.
a factor tree
A factor tree.
8
837 279,3 93,3,3 31,3,3,3
72 36,2 18,2,2 9,2,2,2 3,3,2,2,2
the prime factorization of 32 is 2x2x2x2x2 and the factor tree is 32 8 4 2x4 2x2 2x2
726 363,2 121,3,2 11,11,3,2
352 prime factorization tree
If completed correctly, the bottom branch of a factor tree will be the prime factorization of the number at the top.
23 is a prime number. No prime factorization. No tree.
97 is already prime; no tree required.