Page 238 - Excel 2007 Bible

16_044039 ch11.qxp 11/21/06 11:04 AM Page 195
Introducing Formulas and Functions
This formula will always return the sum of all the data, even if rows or columns are added or deleted. And if
you change the name of Table1, Excel will adjust formulas that refer to that table automatically. For exam-
ple, if you renamed Table1 to be AnnualData (by using the Name Manager), the preceding formula
would be changed to:
=SUM(AnnualData)
Most of the time, you’ll want to refer to a specific column in the table. The following formula returns the
sum of the data in the Actual column:
=SUM(Table1[Actual])
Notice that the column name is enclosed in square brackets. Again, the formula adjusts automatically if you
change the text in the column heading.
Even better, Excel provides some helpful assistance when you create a formula that refers to data within a
table. Figure 11.13 shows the formula autocomplete helping to create a formula by showing a list of the
elements in the table.
FIGURE 11.13
The formula autocomplete feature is useful when creating a formula that refers to data in a table. 11
Correcting Common Formula Errors
Sometimes, when you enter a formula, Excel displays a value that begins with a hash mark (#). This is a sig-
nal that the formula is returning an error value. You have to correct the formula (or correct a cell that the
formula references) to get rid of the error display.
TIP If the entire cell is filled with hash-mark characters, this means that the column isn’t wide
TIP
enough to display the value. You can either widen the column or change the number format of
the cell.
In some cases, Excel won’t even let you enter an erroneous formula. For example, the following formula is
missing the closing parenthesis:
=A1*(B1+C2
If you attempt to enter this formula, Excel informs you that you have unmatched parentheses, and it pro-
poses a correction. Often, the proposed correction is accurate, but you can’t count on it.
Table 11.3 lists the types of error values that may appear in a cell that has a formula. Formulas may return
an error value if a cell to which they refer has an error value. This is known as the ripple effect — a single
error value can make its way into lots of other cells that contain formulas that depend on that one cell.

195