You do a little method called cross multiplication and helps to solve proportions and how to find percents in your case. My iPad won't really show fractions but I'll use the dash marks.
1/10=?/100
Multiply 1 by 100 and you get 100 and then divide by 10 which will get you 10 percent.
Another example would be 4/5=?/100
Again you do cross multiplication and it would be 4 times 100 and you get 400 and then you divide by 5 and the answer is 80 percent.
HOPE THIS HELPED