Trapping Error Values in Their Original Formulas
Error values are not only unsightly but, because they spread so easily to other dependent formulas throughout the spreadsheet, they can be difficult to eradicate. The most professional spreadsheet designers therefore take steps whenever possible to prevent the spread of error values across the spreadsheet by trapping them at their source. The most famous example of where this kind of error trapping is needed occurs in division formulas where the divisor is a cell reference that at times can be blank. As you remember, blank cells as well as cells with text entries carry a zero (0) value as far as formula computations are concerned, so that if they serve as the divisor in a division calculation in a formula, that formula returns the #DIV/0! error value to the cell.