# Excel formula question **URL:** \ **Category:** Factual Questions\ **Created:** [April 29, 2006, 7:21pm UTC](https://boards.straightdope.com/t/excel-formula-question/354764 "2006-04-29T19:21:04Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![robcaro](https://avatars.discourse-cdn.com/v4/letter/r/df705f/32.png) [@robcaro](https://boards.straightdope.com/u/robcaro)\ **Post date:** [April 29, 2006, 7:21pm UTC](https://boards.straightdope.com/t/excel-formula-question/354764/1 "2006-04-29T19:21:04Z")
I have an Excel spreadsheet with 3 columns of various numbers. I am calculating an average of these numbers with the following formula: =(SUM(C5:C100)+SUM(F5:F100)+SUM(I5:I100))/25 My question is, how can I change the average each time I add another number to a column so that I don’t have to change the averaging number, “/25”? ---
**Author:** ![Reply](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/reply/32/15952_2.png) [@Reply](https://boards.straightdope.com/u/Reply)\ **Post date:** [April 29, 2006, 7:32pm UTC](https://boards.straightdope.com/t/excel-formula-question/354764/2 "2006-04-29T19:32:01Z")
Bit confused here. Are you summing up 285 numbers (95 per column, x 3 columns) and then dividing the result by 25? How is that an average? ---
**Author:** ![robcaro](https://avatars.discourse-cdn.com/v4/letter/r/df705f/32.png) [@robcaro](https://boards.straightdope.com/u/robcaro)\ **Post date:** [April 29, 2006, 7:48pm UTC](https://boards.straightdope.com/t/excel-formula-question/354764/3 "2006-04-29T19:48:57Z")
> [@Reply](#): > > Bit confused here. Are you summing up 285 numbers (95 per column, x 3 columns) and then dividing the result by 25? How is that an average? At the present time, the three columns have only 25 numbers and I add more numbers to each column each day. Right now, my average is 131.36. When I add one more number to a column, I will divide by 26 etc… I want the division to increase by one automatically each time I add a number to a column. ---
**Author:** ![Reply](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/reply/32/15952_2.png) [@Reply](https://boards.straightdope.com/u/Reply)\ **Post date:** [April 29, 2006, 7:55pm UTC](https://boards.straightdope.com/t/excel-formula-question/354764/4 "2006-04-29T19:55:17Z")
Oh, okay. In that case, try: **=AVERAGE(C5:C100, F5:F100, I5:I100)** ---
**Author:** ![robcaro](https://avatars.discourse-cdn.com/v4/letter/r/df705f/32.png) [@robcaro](https://boards.straightdope.com/u/robcaro)\ **Post date:** [April 29, 2006, 8:06pm UTC](https://boards.straightdope.com/t/excel-formula-question/354764/5 "2006-04-29T20:06:22Z")
> [@Reply](#): > > Oh, okay. In that case, try: > > **=AVERAGE(C5:C100, F5:F100, I5:I100)** :smack: I should have know that it was an easy solution. I am still learning Excel, so I really appreciate quick knowlegeable answers. I didn’t know about the average command. Many thanks! ---
**Author:** ![Reply](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/reply/32/15952_2.png) [@Reply](https://boards.straightdope.com/u/Reply)\ **Post date:** [April 29, 2006, 8:19pm UTC](https://boards.straightdope.com/t/excel-formula-question/354764/6 "2006-04-29T20:19:51Z")
Sure thing 🙂 By the way, you might want to try Excel’s built-in help the next time you run into a problem. That’s not to say that you shouldn’t ask questions here, but Excel is one of the few programs that actually has decent help. The documentation is _excellent_, actually, and it’s proven very very helpful for me in the past. Microsoft does a really good job with their help files. ---
**Author:** ![robcaro](https://avatars.discourse-cdn.com/v4/letter/r/df705f/32.png) [@robcaro](https://boards.straightdope.com/u/robcaro)\ **Post date:** [April 29, 2006, 8:53pm UTC](https://boards.straightdope.com/t/excel-formula-question/354764/7 "2006-04-29T20:53:11Z")
> [@Reply](#): > > Sure thing 🙂 > > By the way, you might want to try Excel’s built-in help the next time you run into a problem. That’s not to say that you shouldn’t ask questions here, but Excel is one of the few programs that actually has decent help. The documentation is _excellent_, actually, and it’s proven very very helpful for me in the past. Microsoft does a really good job with their help files. I was just thinking that most programs offer little help, so that is why I came to SD for advice. Never fails here! ---
**Author:** ![PosterChild](https://avatars.discourse-cdn.com/v4/letter/p/e274bd/32.png) [@PosterChild](https://boards.straightdope.com/u/PosterChild)\ **Post date:** [April 30, 2006, 5:59am UTC](https://boards.straightdope.com/t/excel-formula-question/354764/8 "2006-04-30T05:59:24Z")
> [@robcaro](#): > > I was just thinking that most programs offer little help, so that is why I came to SD for advice. Never fails here! FYI: There are also a number of commands to count the number of cells that have values/numbers/blank, etc. - I agree that the help program can be helpful. - Also: i’ve found some amazing formula help googling for excel info.