How can the sum formula possibly add 12 extra decimal places?

I am trying to get the actual total of a column of numbers using the sum formula, which I use all the time, and have never had this problem before.
There is not a single number in the column that has more than 2 decimal places, yet somehow the sum formula has added 12 extra decimal places into the answer... I've tried using the round formula, I've tried adding the numbers in a new workbook, I've tried retyping all the numbers, I've separated out the decimal values & confirmed that is no more than 2 digits in all numbers, but the answer still seems to be wrong.
Anyone know how I can fix this problem?

No... What I'm looking for is how can adding up #'s that have a maximum of 2 decimal places possibly add up to a # with 12 decimal places. It's not mathematically possible. The formatting is like that to show that the numbers being added only have max 2 decimal places, while the added column has 14 decimal places. Formatting it to 2 decimal places does not give me the correct answer, the answer still has 14 decimal places whether you can see them or not.

yes, post #3 is my issue

It's an issue with Floating Point Precision (google it, it's a documented issue in Excel)

Solution is to round the sum
=ROUND(SUM(A3:A61),2)

Change the 2 to whatever decimal is an acceptable level of accuracy for your purpose.

that would work in my table part... any suggestions on how to manipulate that in my end-result pivot table? I didn't mention that part because I though the problem could be fixed at the source, sorry

Thank you ConneXionLost, that article helped, fixed it at the source