Hello,

Please be gentle, its my first post.

I use an xl spreadsheet daily that adds up data according to the adjacent tag, then compares the sums with an if statement as a check. Its worked across several versions of xl and for the last 6 months in xl 2010 with no problems until today when the check indicated an error. The totals matched, so to rule out any formatting, lookups etc I typed the raw data into a new blank spreadsheet. There are only 5 numbers that run to 1dp, four sums and 1 if statement. The error persisted, so I subtracted and found a small difference (-0.00000000009) so I expanded the number of decimal places to 10 and found the cause of the error .... -77758.7 + 358938.9 + 94993.6 + -383295.6 + 72165.1 = 65043.30000000010.

I've tried the spreadsheet on another 'corporate clone' Dell E6320 notebook and the same error happens - but have no older xl version to test or other machine. I attach a screengrab from my system and the spreadsheet for you to look at.

I understand rounding errors with recurring numbers, but in simple addition to 1dp I can't follow it. I've found a work around by changing the calculation accuracy to precision as displayed but I'd like to know why its happenning in the first place. Any explanation would be greatly appreciated.

Excel Example Sheet.xlsx
Capture.JPG

Thanks, in advance, for your help.