"or" functions that can be one set of data or another..

I am trying to make a sheet showing calculations of any 2 variables I put in. If you look at this link you can see all those calculations that give you any of the 4 things if you have 2 of the others. So in the end, all I want is for the top row to say volts amps ohms watts, and you put in 2 variables under it, then you have the same 4 headers only going vertically down a column and using those 2 variables, it calculates and shows what everything is. Obviously the 2 variables I put in would just be copied to the same 2 variables. Heres what I mean, \1

You can see how I put in 2 things on the top row and got all the results on the column. I don't know how to do it. I tried something like =b5*b2 or b5/b3 but it doesnt know what "or" means so I have no clue.