Microsoft Office Tutorials and References
In Depth Information
Ordering Up Your Results
=4*(5+7)
You get the idea. Excel resolves this kind of ambiguity with a set of orders of operation—a kind of
priority listing which declares which operation takes precedence—that is, is calculated first—in a
formula. (In the cases above, the values flanked by parentheses are treated as a unit.) The order reads
like this:
Parentheses
Exponents
Multiplication
Division
Subtraction
Addition
Let’s illustrate this hierarchy with a few cases. This formula:
=4+5/2
results in an answer of 6.5. It divides 5 by 2 and then adds 4—because priority goes to division over
addition.
This formula:
=4*5/2
results in 10, because the multiplication —4 times 5—is carried out first . That result—20—is then
divided by 2.
This formula, however:
=4*(5/2)
also yields 10, but this time because the parenthetical expression—(5/2) that is, 2.5—has priority over
any other operation.
Now let’s get back to our regularly scheduled program—this matter of adding numbers via a
formula. While the method we recounted above surely works, it conceals a problem. What if you need to
add 20,000, or even 200, numbers? You won’t want to click on each and every one of those cells as per
our initial method—and, given Excel’s cell character limit, you may not be able to do it anyway. So
what’s the alternative?
Good question. The answer takes us to the first and most important of Excel’s built-in operations, or
functions , called SUM . How does SUM work? For introductory purposes, we’ll demonstrate the standard
way to implement SUM in a worksheet—with the AutoSum command, which is actually stored in two
different tabs (remember that term?) in slightly different guises— Home and Formulas , shown in Figures
3–4 and 3–5:
Figure 3–4. The location of AutoSum in the Home tab
 
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