Excel 2007and Excel Services 2007 involving calculation

Excel 2007and Excel Services 2007 involving calculation of numbers around 65,535.This issue was introduced when we were making changes to the Excel calculation logic in the Office 2007 time frame.  Specifically, Excel incorrectly displays the result of a calculation in 12 very specific cases (outlined below).  The key here is that the issue is actually not in the calculation itself (the result of the calculation stored in Excel’s memory is correct), but only in the result that is shown in the sheet.  Said another way, =850*77.1 will display an incorrect value, but if you then multiply the result by 2, you will get the correct answer (i.e. if A1 contains “=850*77.1”, and A2 contains “=A1*2”, A2 will return the correct answer of 131,070).

So what, specifically, are the values that cause this display problem?  Of the 9.214*10^18 different floating point numbers (floating point) that Excel 2007 can store, there are 6 floating point numbers (using binary representation) between 65534.99999999995 and 65535, and 6 between 65535.99999999995 and 65536 that cause this problem.  You can’t actually enter these numbers into Excel directly (since Excel will round to 15 digits on entry), but any calculation returning one of those results will display this issue if the results of the calculation are displayed in a cell.  All other calculation results are not affected.

fixes for this issue in Excel 2007 and Excel Services 2007 are available for download from the following locations:

Excel 2007: http://download.microsoft.com/download/6/1/3/61343075-aa12-4152-a761-fccc16d6cef4/office-kb943075-fullfile-x86-glb.exe
64-bit Excel Services 2007: http://download.microsoft.com/download/c/d/c/cdcccd84-86cd-4199-b01c-1df2dac66534/office-kb943076-fullfile-x64-glb.exe
32-bit Excel Services 2007: http://download.microsoft.com/download/c/d/c/cdcccd84-86cd-4199-b01c-1df2dac66534/office-kb943076-fullfile-x86-glb.exe

KB Articles have been posted as well:

Excel 2007: http://support.microsoft.com/default.aspx/kb/943075/
Excel Services 2007: http://support.microsoft.com/default.aspx/kb/943076