We can restate this problem as:
$13 is what percent of $52?
First, let's call the percent we are looking for "p" or p%.
"Percent" or "%" means "out of 100" or "per 100", Therefore p% can be written as p100.
When dealing with percents the word "of" means "times" or "to multiply".
Putting this all together we can write this equation and solve for p while keeping the equation balanced:
$13=p100×$52
$13=$52p100
$13×100$52=$52p100×100$52
$1300$52=$52p100×100$52
$1300$52=$52p100×100$52
130052=p
25=p