One is not really an error, it is more like GIGO in the Average function:
https://exceloffthegrid.com/excels-average-function-the-hidd...
The other one is actually an error due to internal number storing (floating point):
https://docs.microsoft.com/en-us/office/troubleshoot/excel/f...
More generally there is 15 digit precision that can create issues, but the "real bug" was in Excel 2007
77.1 multiplied by 850 gave apparently 100,000 instead of 65,535
https://news.ycombinator.com/item?id=59392
https://www.journalofaccountancy.com/issues/2014/mar/excel-c...
One is not really an error, it is more like GIGO in the Average function:
https://exceloffthegrid.com/excels-average-function-the-hidd...
The other one is actually an error due to internal number storing (floating point):
https://docs.microsoft.com/en-us/office/troubleshoot/excel/f...
More generally there is 15 digit precision that can create issues, but the "real bug" was in Excel 2007
77.1 multiplied by 850 gave apparently 100,000 instead of 65,535
https://news.ycombinator.com/item?id=59392
https://www.journalofaccountancy.com/issues/2014/mar/excel-c...