Thom's reply is very concise and just what you are looking for.
Jdelvin and Redsy's suggestions are equally good.
Use the Auto Sum function, or enter formulas manually. When you get fluent with spreadsheets, start using premade Macros, or create your own.
After the Macros get mastered, make super tweeked versions using VBA (as Thom mentioned).
When you get fluent with this, you will begin to eat only Pizza and Doritos, wear a pocket protector, complain about how Hollywood "has no clue about machines, machine language, assembly language, anything related to Astrophysics, etc.", your hair will become wild, and you will lose your social life!
just kidding! This only happened to me! (and a few others, too).
Spreadsheets are extremely useful tools - which are able to perform simple things to very complex things.
And like Bjarney said, "Then step into the Database world, and you can run an entire corporation" or something like that
Software applications have great potentials ... for the right person(s). If a person is comfortable doing tasks without any computer assistance, there is no reason to change - unless that person is 100% sure they can benifit from a computer's assistance.
The learning curve / initial learning expense can be very large, and last for several weeks - possibly even several months - to use an appication at even a basic level. Just don't get discouraged!
There is a person (one project manager) at work, who has only been using a PC for about 1 year. This person works it very well, and learns a lot from us "well seasoned" users every day, which makes things even easier + productive for that person.
Sice I have been there, have noticed that this person has evolved greatly in "PC Fluency".