Whether you have a hard time figuring how much your share of the bill is or what the right tip amount is once you're done dining out, if you are an iPhone carrying member, Rivera Labs (based in Puerto Rico) released as its fourth app, Friendly Tip Calculator which does all the leg work for you.
In the end, with or without tech, do the right thing, give the right tip.
(* Image from pages of app creator, Rivera Labs)