If you are using Excel 2007 at office or at home, you might be surprised to know that while it can do complex calculations accurately, Excel 2007 has trouble doing simple multiplication.
While it is hard to believe, Excel makes mistakes multiplying 77.1 by 850, 10.2 by 6,425 and 20.4 by 3,212.5. Basically Excel 2007 has problems with certain calculations where the result is 65,535 or 65,536. The problem was first identified with 65,535 but later tests showed a similar phenomenon with 65,536 as well.
Microsoft employee David Gainer says that Excel was actually performing the calculations correctly, but when it comes time to show the answer on the screen, it messes up. Gainer said the bug is limited to six numbers from 65,534.99999999995 to 65,535, and six numbers from 65,535.99999999995 to 65,536.
The number 65,536 is 2 multiplied by itself 16 times, and a common delimiter in programming, which relies on binary numbers. The “problem” decimals 65,534.99999999995 and 65,535.99999999995 each have 16 characters, and Excel may be having trouble interpreting values between those and the next round number.
Hotfixes
Microsoft has already announced a Excel 2007 hotfix package for the issue. You can download it here. You may also want to read the KB article on this here.
Microsoft is in the process of adding this fix to Microsoft Update so that it will get automatically pushed to users running Excel 2007. Additionally, the fix will also be contained in the first service pack of Office 2007.
