Using formulas

From Reporting Cookbook: www.forjournalists.com/cookbook

What makes Excel a valuable tool is its ability to do a calculations on a list of numbers quickly.

It does so using formulas.

Formulas can sum a list of numbers, take the average or find the largest value, among many, many other things. Some formulas are hideously complex -- but you can get a lot of mileage out of Excel knowing only a few simple ones.

Let's look at the formula to sum a group of numbers.

Say we want to sum the direct loans made by the U.S. Department of Agriculture in 2005:

All formulas begin with the = sign. So in the cell where we want to compute the sum, enter =

Then type SUM and a left parenthesis:

Then the range of cells you want to add together. In this case, we want to add cells B2 to B8. We write this as B2:B8.

Type the closing parenthesis, so our formula becomes =SUM(B2:B8) and hit enter.

That gives our sum: $20,419,000,000.

If we wanted to determine the average, the formula would be =AVERAGE(B2:B8)

If we wanted to find the largest number, the formula would be =MAX(B2:B8)

If we wanted to find the smallest number, the formula would be =MIN(B2:B8)

If we wanted to count the number of cells being added together, the formula would be =COUNT(B2:B8)

Summing a list of numbers is such a common task there's a shortcut for doing it. On the toolbar, there is an "AutoSum" icon in the form of a Greek Sigma:

If you have a column of numbers you want to add together, click on the first blank cell below the column and then click on the AutoSum icon.

When you do that you'll see that Excel fills out the formula for you and tries to guess which numbers you're adding up. In this case, it guesses wrong because it includes the year in the numbers being summed. You don't want that, so you'll have to manually edit the formula. Often, though, it does get it right.

You can learn more by taking Microsoft's free online training course on using formulas.