the first method you have is good.

if someone asks what is 20% of 60, they are asking ?

it's a good way to lay it out, especially since you can pretty much transliterate the equation from the english sentence, so it is easy to remember.

since "percent" means "out of 100" and "of" in math means "multiply", it's easy to see that "20 percent of 60" is the same as "20 over 100 times 60" so that's good