## Microsoft Excel 2003 Functions and Formulas

### Check if a Value is a Number

Summary: Prevent Spreadsheet errors in Excel 2003 by ensuring entered values are actually numbers.

Microsoft Excel 2003 may report errors in a spreadsheet if a calculation involves a value expected to be a number, but isn't. To help prevent this from happening, use the =isnumber function:

=isnumber(VALUE)

VALUE is a value, cell, or function result

This function is useful when combined with other functions. For example, assuming the following spreadsheet of quarterly profits (in thousands):

`    A                                                   B1   1st Quarter (in \$k)                                 \$256.002   2nd Quarter (in \$k)                                 \$113.003   3rd Quarter (in \$k)                                 John4   4th Quarter (in \$k)                                 \$456.005   6   =IF(ISNUMBER(B1),"","1st Quarter Value is Invalid")7   =IF(ISNUMBER(B2),"","2nd Quarter Value is Invalid")8   =IF(ISNUMBER(C1),"","3rd Quarter Value is Invalid")9   =IF(ISNUMBER(B4),"","4th Quarter Value is Invalid")`

As you can see, the value for the 3rd quarter is invalid. In fact, cell A8 tells us so with this result:

3rd Quarter Value is Invalid

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