If you are rounding the number by controlling the number of decimal places, you have not actually rounded the number--you've just changed the cell formatting. You can see this if you look up at the formula bar.
If you typed 1.12 into cell A1, then formatted the cell to show no decimal places, you'll see 1 in the cell but 1.12 in the formula bar.
To actually round the number, excel offers formulas that will likely meet your needs. Try ROUND, for instance.
tj