为什么excel四舍五入，但仍显示超过2个小数点

I have a set of numbers that was rounded of to 2. When I sum a range, i ended on a cell which shows 762,078.31. I copied this cell and paste value and it actually shows 762078.31. I increased decimal and it still shows 762078.3100. But on the 'formula bar' it shows as 762078.309999999. I have a set of numbers that was rounded of to