If you can easily change the denominator to 10 or 100 (or any power of 10), do it!
 

Convert1 / 5
 
to a percent:

1 / 5 = ( 1/5 ) x ( 20/20 ) = 20 / 100 = .20 = 20%


TRY IT:

Convert1 / 4
 
to a percent:

Here's one that's a little trickier:

Convert1 / 16
 
to a percent:

1 / 16 = ( 1 / 2^4 ) x ( 5^4 / 5^4 ) = 5^4 / 10^4 = 625 / 10,000 = .0625 = 6.25%

Yes, you CAN have a percent
that still has a decimal in the front!

Weird, huh?