To determine the prime factors of a number:
Try to divide the number by the lowest Prime number, which is 2. If it divides evenly mark that number down as one of the prime factors, and continue with the result, trying to divide that prime factor into it. Continue dividing that prime factor into the results until it no longer divides evenly. If it does not divide evenly, move to the next lowest prime number and repeat the process until you have a result that is a prime number. Now you have all the prime factors.
Example: Find the prime factors of 128.
The prime factors are in bold.
128 ÷ 2 = 64
64 ÷ 2 = 32
32 ÷ 2 = 16
16 ÷ 2 = 8
8 ÷ 2 = 4
4 ÷ 2 = 2 which is a prime factor and thus the final prime factor.
Therefore, the prime factors of 128 are 2, 2, 2, 2, 2, 2, and 2; the prime factorization is 2 x 2 x 2 x 2 x 2 x 2 x 2.
Example: Find the prime factors of 108.
108 ÷ 2 = 54
54 ÷ 2 = 27
27 is not divisible by 2, so try 3.
27 ÷ 3 = 9
9 ÷ 3 = 3 which is a prime factor and thus the final prime factor.
Therefore the prime factors of 108 are 2, 2, 3, 3, and 3; the prime factorization is 2 x 2 x 3 x 3 x 3.
Example: Find the prime factors of 1463.
1463 is not divisible by 2 or 3 or 5, but it is divisible by 7.
1463 ÷ 7 = 209
209 is not divisible 7, so try the next prime number, which is 11.
209 ÷ 11 = 19 which is a prime factor and thus the final prime factor.
Therefore, the prime factors of 1463 are 7, 11, and 19; the prime factorization is 7 x 11 x 19.
Another way to determine the prime factors is to use a factor tree. To make a factor tree, find two numbers whose product is the given number. Then, if those numbers are not prime, do the same for them. Continue until all numbers are prime.
Example: Find the prime factors of 54 using a factor tree.
54
6 x 9
2x3 x 3x3
Therefore, the prime factors of 54 are 2, 3, 3, and 3; the prime factorization is 2 x 3 x 3 x 3.
For other examples of factor trees, see the related question on factoring terminology.
you find it by using exponents and by dividing the two numbers
you do a mutiple of that to get the number you re factoring by then make prime factor tree
Multiply prime numbers or prime factors to find their product.
1720 860,2 430,2,2 215,2,2,2 43,5,2,2,2 The prime factors of 1720 aren't consecutive.
it means to find out if the number is composite or prime
The prime factors of 28 are 2 and 7. Their sum is 9.
Once all the prime factors of a number have been found, the number of factors the number has and what they are can be found. I'd be finding the prime factors first before finding all the factors of a number, so I'd rather find all the prime factors as it means I can stop before I have to do more work in finding all the factors.
Multiply prime numbers or prime factors to find their product.
The prime factors of a squared number are the prime factors, if any, of its square root.
Once you have the prime factorization, it is much easier to find the factors, the proper factors, the GCF and LCM.
The prime factors of 24 are 2 and 3.
The prime factors of 87 are 3 x 29
The prime factors of 50 are: 2 and 5
1720 860,2 430,2,2 215,2,2,2 43,5,2,2,2 The prime factors of 1720 aren't consecutive.
Prime factorization is when you find all the prime factors of a number.
it means to find out if the number is composite or prime
The prime factors of 28 are 2 and 7. Their sum is 9.
List all the factors. Select the ones that are prime numbers.
The prime factors of 30 are: 2 + 3 + 5 = 10