Excel multiplication bug unearthed

If you have 850 of something, you might want to hold off multiplying that number by 77.1, at least if you're using Microsoft Office 2007's version of Excel. A bug recently found in the spreadsheet will return an incorrect answer.

Excel spreadsheet bug screen shotThe bug appears to be only in the 2007 version. Discussion has been ongoing over the extent and nature of this problem.

When the formula '=850*77.1' is entered in an Excel cell, the wrong answer 100,000 is returned. The correct answer is 65,535.

The bug was first reported in the Microsoft.public.excel newsgroup. According to participants of that group, when those two numbers are entered as a formula, or entered as part of the =SUMPRODUCT function, the incorrect number appears.

Update (9/26/07): Microsoft has issued a statement that confimed that Microsoft Office Excel 2007 has a flaw "that affects some calculations where the product should equal 65,535." It goes on to say that the company is "currently in the process of developing and testing a fix for the flaw."

About the Author

Joab Jackson is the senior technology editor for Government Computer News.

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