Excel 2007 bug shows wrong answers to simple multiplications

This is a follow-up post to my earlier one about a bug in the way Excel 2007 displays the results of certain calculations. Read that one first of you have not already done so.

A few people in the comments thread in the Excel team blog post about the bug seem to have some misconceptions about the seriousness of the problem. Some have asked how often it is likely to come up, implying that they think it is vanishingly unlikely. This seems to be particularly those who have misunderstood that the example of 850*77.1 is only one simple example which is easy to remember and to type, but there are several more simple ones as well as thousands of other combinations which lead to the buggy result (due to floating point rounding errors in the calculation hitting a result which is sufficiently close to 65,535 to cause the false display of 100,000). Nine examples are shown in the screenshot below, and in a table you can easily copy and paste to try this for yourself.

» See some simple examples and find out more about functions which reproduce the error, and which ignore it safely»

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