What are the factors of 42?

##1, 2, 3, 6, 7, 14, 21, 42##

##42## can be factored as a product of primes:

##42 = 2*3*7##

So combining them in all possible ways we find that the positive whole factors are:

##1, 2, 3, 6, 7, 14, 21, 42##

One way to find the factors is to try each number in increasing order. If you find a factor ##k## then ##42/k## will be a factor too, stop when ##42/k < k## :

##1, 42##

##2, 21##

##3, 14##

##color(red)(cancel(color(black)(4)))## No

##color(red)(cancel(color(black)(5)))## No

##6, 7##

Done!