Microsoft Office

Part IV
Using Advanced Excel Features
Notice that the negation operator symbol is exactly the same as the subtraction operator symbol. This, as
you may expect, can cause some confusion. Consider these two formulas:
=-3^2
=0-3^2
The first formula, as expected, returns 9. The second formula, however, returns –9. Squaring a number
always produces a positive result, so how is it that Excel can return the –9 result?
In the first formula, the minus sign is a negation operator and has the highest precedence. However, in the
second formula, the minus sign is a subtraction operator, which has a lower precedence than the exponentiation
operator. Therefore, the value 3 is squared, and the result is subtracted from zero, which produces a
negative result.
Using parentheses, as shown in the following formula, causes Excel to interpret the operator as a minus sign
rather than a negation operator. This formula returns –9.
=-(3^2)
Formulas are not calculated
If you use custom worksheet functions written in VBA, you may find that formulas that use these functions
fail to get recalculated and may display incorrect results. To force a single formula to be recalculated, select
the cell, press F2, and then press Enter. To force a recalculation of all formulas, press Ctrl+Alt+F9.
Actual versus displayed values
You may encounter a situation in which values in a range don’t appear to add up properly. For example,
Figure 32.3 shows a worksheet with the following formula entered into each cell in the range B3:B5:
=1/3
FIGURE 32.3
A simple demonstration of numbers that appear to add up incorrectly.
Cell B6 contains the following formula:
=SUM(B3:B5)
All the cells are formatted to display with three decimal places. As you can see, the formula in cell B6
appears to display an incorrect result. (You may expect it to display 0.999.) The formula, of course, does
return the correct result. The formula uses the actual values in the range B3:B5, not the displayed values.
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