I have just found a problem in a very simple spreadsheet (explained below) for which I do not understand the reason.

A1: 7280
A2: 6640
B2: difference formula =A1-A2 [cell displays (640.00)]
C2: division formula =614.73/A2 [cell displays .09]
D2: multiplication formula =B2*C2 [cell displays 59.25]

I inserted these identical cells within an Open Office spreadsheet. The result was the same as above.

However, for the cell displaying 59.25, my wife showed a value of 57.60 on her calculator, which matched a manual effort.

I changed the D2 formula and instead of using cell C2 (a formula) I used a different cell wherein I manually entered the result of the C2 formula, .09. The result then matched the calculator result of 57.60

Can someone explain what is going on?