How do you simplify the fraction #10/30#?
It's best to begin by determining every possible integer (whole number) that the numerator (the top number) and denominator (bottom number) are able to be divided by. In other words, make a list of every number that each value can be evenly split into.
Notice that each of those numbers can evenly make up 10 and 30, respectively.
Now you can compare the lists and find the biggest number that both have in common. It appears that it's 10.
How many times does 10 go into 10? Once.
How many times does 10 go into 30? Three times.
You can use these numbers to simplify, getting the following: