Question

which of the following numbers are factors of 120? how do you know?
a)2
b)5
c)7
d)12
e)120

Answer 1

You can factor it out like this.

120
/ \
2 60
/ \
2 30
/ \
2 15
/ \
3 5

by factoring out to just prime number you can see which numbers 120 is divisible by. Also is you multiply some of these factors together you can find other factors. oh and don't forget the number 1 and the number itself (in this case 120) are factors you can find easy without factoring at all).

so the string of factors you can work with is 2*2*2*3*5

good luck