inputsettings

Hi, Im not a developper Do you help me , i would like to: 1/first count the diffrence betwen 2 numbers in 2 variables Exemple: Var1: 30 and Var2= 5 How to have the result ? 30- 5= 25 (result) 2/After, it is possible to set the result in the"setting parameter" I want to use this result to use...

How can i implement this switch? i want these options to have function thru input settings. I've tried string and variable already but im not in right mind today to think. lol Thank you if someone will help me with this. :D