How would you use a factor in the real world?

Depending on what you really mean..................

The factor 3 as in $3 + $5 =$8 could be that your friend owes you 3 dollars from

you paying him for nachos at the pool, and 5 more dollars for you paying him to get

a muse song on itunes. Or maybe you have the problem $47+$92 for groceries and water bills. That would equal your entire bill for groceries and water. The answer is

$141. Or maybe subtraction factors..... You have groceries and water and electricity

and rent to pay this month. groceries are 92$, water is 47$,electricity is 400$, and rent is 700$ .You have already payed water and groceries. That's 141$ payed subtracted by the total amount of money which is left to pay. That's 141 dollars subtracted by 1239 =1098 dollars left to pay.

All of the factors I have used in this answer is 3,5,47,92,and 700. the rest of the factors are also answers because I subtracted 141 from 1239 which was the answer of the factors for the bills: 92,47,400, and 700.