I fell asleep thinking about backwards percentages and woke up with this idea. 

I’m not sure if the layout is intuitive, I’d appreciate your thoughts. 

I must have tried to iterate this about 5 times to get it to ‘work’.  Hopefully I’ve got my working correct and it does ‘work’.  You’ll know what I mean by that if you work through it! 

Download PDF Here

Credit: @chrismcgrane84