I believe it is commutative property cause the numbers didn't change instead they just switched places in the equation.
6/x=27
times both sides by x
6=27x
divide both sides by 27
6/27=x
2/9=x
the missing number is 2/9
If you take 25% off of 16 you would pay $12(75% left to pay).
62.5% is the percent off 5/8