Excel 2007 gets its sums wrong
Excel 2007 appears to have a problem with simple multiplication.
The unsual bug was posted on a Usenet group by Mohlam Serry, who discovered that asking Excel to multiply 850 x 77.1 produced a wrong answer.
The result should be 65,535, but is instead returned as 100,000. You can replicate the problem by placing the formula =850*77.1 into an empty cell.
Some other combinations of sums that equal 65,535 are also affected by the bug, but others are returning the correct number.
Th number 65,535 should be familiar to programmers, as it is the highest number that can be stored in a 16-bit unsigned binary number. A problem with transitioning between 16-bit and 32-bit numbers may well be the cause.
Microsoft has been informed of the problem, but couldn’t comment at the time of going to press.