N function
Returns a value converted to a number.
Syntax
N(value)
Value is the value you want converted. N converts values listed in the following table.
If value is or refers to 
N returns 
A number 
That number 
A date, in one of the builtin date formats available in Microsoft Excel 
The serial number of that date 
TRUE 
1 
FALSE 
0 
An error value, such as #DIV/0! 
The error value 
Anything else 
0 
Remarks

It is not generally necessary to use the N function in a formula, because Excel automatically converts values as necessary. This function is provided for compatibility with other spreadsheet programs.

Excel stores dates as sequential serial numbers so they can be used in calculations. By default, January 1, 1900 is serial number 1, and January 1, 2008 is serial number 39448 because it is 39,448 days after January 1, 1900. Excel for the Macintosh uses a different date system as its default.
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.

