This next method is probably beyond the pre-algebra level. It's really not that bad, but it will seem a bit creepy at first. I think it's just the name!
The Euclidean Algorithm:
An algorithm is just a list of steps to work through -- like a process where you do the same thing all the time.
I need to show it to you with letters first:
|If you want to find||, you start with|
In English (haha), you put b into a as many times as it will go (q) and, then, get the remainder.
Here it is with numbers: