82.19777664*33.20088775

Results

Windows Calculator = 2,729.039155524212

Firefox Add-on Calculator = 2729.039155524212

Libre Office Calc = 2,729.039155524210

Microsoft Excel 2010 = 2,729.039155524210

As you can see, the calculators agree on the numbers and the spreadsheet programs agree on the numbers, but as you can also see the 2 different types of programs agreed on different numbers - it appears the spreadsheets rounded the last number down to zero.

I allowed for 12 decimal places in the spreadsheet programs, I even added decimal places to 14 or 15 and I got the same results - with additional trailing zero's in the additional decimal places in the spreadsheet programs.

Anyone have any idea how and why these programs are handling the math this way? Thanks for any insight anyone can shed on this riddle