Simple math
 

It would be nice in the Gallons field for a fuel up if I could enter something like "28.294+4.491", and let Fuelly do the addition for me when saving the fuel up, rather than having to break out the calculator.

So many pumps cut off the transaction after $75 - $100 that I often have to make two transactions for a single fuel up and add them together.

Whoa, I've never run into that before. Is this for very large gas tanks in a truck or something?

Unfortunately, the way most web sites take data is in the format of numbers, and throwing a plus sign in there can break a lot of things. If we can think of an easy way to do this, we'll think about adding it, but sticking with a calculator for now is probably be the way to go.