20% of a number is x what is 100% of the number assume x is greater then 0

                           x is 20% of Number

                           x = (0.2) x (number) .

Divide each side by  0.2 :     Number =  x / 0.2 

                                             Number = 5x .

'x' can be anything, even zero.  This equation works for x=any number.