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Let's say you want to find out how many inventory items are not profitable (total inventory – profitable items) or how many employees are approaching retirement age (total employees – employees under 55). There are several ways to subtract numbers.
What do you want to do?
Subtract numbers in a cell
Subtract numbers in a range
Subtract numbers in a cell
To do this task, use the  (minus sign) arithmetic operator.
For example, if you type the following formula in a cell:
105
The cell displays the following result:
5
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Subtract numbers in a range
To do this task, use the SUM function. Adding a negative number is the same as subtracting.
Example
The example may be easier to understand if you copy it to a blank worksheet.
How to copy an example
 Create a blank workbook or worksheet.
 Select the example in the Help topic.
Note Do not select the row or column headers.
Selecting an example from Help
 Press CTRL+C.
 In the worksheet, select cell A1, and press CTRL+V.
 To switch between viewing the results and viewing the formulas that return the results, press CTRL+` (grave accent), or on the Formulas tab, in the Formula Auditing group, click the Show Formulas button.

A 
Data 
15,000 
9,000 
8,000 
Formula 
Description (Result) 
=A2A3 
Subtracts 9,000 from 15,000 (6,000) 
=SUM(A2:A4) 
Adds all numbers in the list, including negative numbers (16,000) 

Function details
SUM
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