In Excel 2007 formulas are instructions for Excel to carryout an action, generally a calculation. Formulas can perform calculations, format cells and contents, and more. Formulas always start with =.
Functions are builtin, predefined formulas.
Formulas can be entered directly in the cell or in the Formula Bar.
Common Excel 2007 Formulas
Formula
Description
SUM
Adds all of the numbers in a range of cells.
AVERAGE
Calculates the average for a range of cells.
TODAY
Inserts today's date.
Inserting Formulas
To insert a formula in Excel 2007,
Click the in the cell for the formula. In the example below, this is cell B6.
Type, =SUM(.
Click in cell B2. (Alternately, type B2:)
Click in cell B5. (Alternately, type B5)
Type ). The formula now looks like this:
Press Enter. The sum of the formula is displayed.
Arithmetic
Arithmetic operators are used to perform basic mathematical calculations.
The arithmetic operators are:
Description
*
Multiplication
/
Division
+
Addition

Subtraction
%
Percent
^
Exponent
Addition is a mathematical operator. Let's suppose I want to add the contents of cells A9 and A10 in our worksheet.
To do this,
Click in the cell for the formula. In the example below, this is cell A11.
Type, =.
Click in cell A9. (Alternately, type A9.)
Type +.
Click in cell A10. (Alternately, type A10.) The formula now looks like this:
Press Enter. The results of the formula display.
Comparison
Comparison operators are used to perform comparisons between two values. For example, comparison operators can be used to see if the contents of one cell are greater than the contents of another. The comparison will return TRUE or FALSE as the result.
The comparison operators are:
Description
=
Equal to
>
Greater than
<
Less than
>=
Greater than or equal to
<=
Less than or equal to
<>
Not equal to
Let's suppose I wanted to see if the amount in cell A1 was greater than the amount in cell A2. I can use a comparison operator to do this.
To use a comparison operator,
Click in the cell for the formula. In the example below, this is cell B2.
Type =.
Click in cell A1. (Alternately, type A1.)
Type >.
Click in cell A2. (Alternately, type A2.) The formula looks like this:
Press Enter. The results of the formula display as TRUE because cell A1 is greater than cell A2.
Text Concatenation
The ampersand & is used to join to strings of text into a single string of text.
For example, let's suppose you have the word sea in one cell and shore in another.
I can combine the text in both cells using concatenation to produce the word seashore.
To concatenate cells A3 and B3 into seashore, type =A3&B3 into cell C3.
Press Enter. Cells A3 and B3 are concatenated in cell C3.
Reference
Reference operators are used to combine cell ranges in calculations.
The reference operators are:
: (colon)
: is used to include all of the cells between two cell addresses. It represents THROUGH or BETWEEN. For example, A1:A4 refers to cells A1 through A4, or cells A1, A2, A3 and A4.
, (comma)
, is used to combine multiple references into one reference. It represents AND. For example, A1:A4,B1:B4 refers to cells A1:A4 and B1:B4.A1,A2,A3,A4 and B1,B2,B3,4
(space)
(space) is used as the intersection operator. It represents BOTH or COMBINED. It allows you to evaluate cells that are common to two references or ranges.
NOTE: Named Ranges should be used when working with the Intersection Operator. For more information, see the Using Names to Work with Ranges section.
For example, let's suppose we have a worksheet displaying widget sales for our four regions over the last four quarters:
We want to find the total Quarter 3 widget sales for the South and East regions combined.
To find the total Quarter 3 widget sales for the South and East regions combined,
Setup Named Ranges for each region and quarter (e.g., "North" cells B2:E2; "Quarter1", cells B2:B5).
Type =SUM(South:East Quarter3).
Notice the ranges highlighted by Excel and the space between East and Quarter3.
Press Enter. The results display.
Order of Operations
Multiple operators are often used in a single formula. Because of this, Excel uses a ranked system to determine the order in which operators are used. Excel's order of operations is:
Reference Operators
:
,
(space)
Arithmetic Operators
 (Negative; not subtraction)
%
^
* and /
+ and 
Concatenation Operator
&
Comparison Operators
=
>
<
>=
<=
<>
Relative and Absolute Referencing
Relative Referencing
By default cell references are relative. This means that when a formula is copied and pasted into another cell (or range of cells) the cell references in the formula will update to reflect the formula's new location.
For example, I want to find the sum of cells A1 and A2. I type this formula:
The result is 40.
If I copy and paste the formula into cell C2, Excel gives me the correct answer of 42 for cells A2 +
B2.
Notice that the Formula Bar displays =SUM(A2+B2) rather than the copied =SUM(A1+B1). Excel has automatically updated the formula for me.
How does this work? Rather than simply copying and pasting the cell references, Excel notices that in my original formula I was referring to cell A1 which is 2 cells to the left and cell A2 which is 1 cell to the left. Taking this into account, Excel updates my formula in cell C2 so that it is referring to cells that are 2 cells to the left and 1 cell to the left, or A2 and B2.
Absolute Referencing
Absolute cell references always refer to the same cell. Cell references are not updated in formulas when copied and pasted to new locations. If the position of a formula changes, the absolute cell reference does not change.
To signify an absolute reference, place a $ before the column and row references. For example, $A$1 is an absolute reference to cell A1.
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