You divide the number by different integers, until you find a factor (or don't). If you do a division and get a whole number, it means the number by which you divided is a factor. For example, to find the prime factors of 70, if you try dividing by 2, you get a whole number (35), so you can split up 70 into two factors:70 = 2 x 35
2 is a prime factor; you need to continue looking for additional factors for the number 35.
The factors you must try out in each case are the different prime numbers, starting with 2. If you don't remember the prime numbers, you can divide by 2, then by all odd numbers (starting with 3).
It isn't necessary to try out a factor larger than the square root of the number. Thus, for all numbers up to 120, it's enough to try out the division by 2, 3, 5, 7. For numbers larger than that, you may need to try additional factors.
2*2*5*5
99 = 32 x 11
2 x 3 x 5
32 x 52
By dividing your number by prime numbers until all the factors are prime. 210 105,2 35,3,2 7,5,3,2
23x19
13,2,4,7,3,1,8,358,24,27,792,45,89,32 and 97.
152 = 2x2x2x19.2,2,2,19
The answer is 2x5x2 3
2*5*19
1, 2 and 13
3*3*7
17*17 = 289
49 = 7*7
The prime factorization of 39 is: 13 * 3 *1
The prime factorization of 88 is 2*2*2*11.
45 = 3² x 5