Using error-checking functions ISERR, ISERROR, IFERROR, and ISNA

- Excel has a number of error checking functions,…and if you were looking for them in the help system,…you can go to the Formulas tab and choose Reference,…and you'll find most of them under Information Functions,…for example, ISERROR, ISERR, and a few more here, too.…ISNA, not exactly an error, but it would help us find…those kinds of functions, as well.…And you'll also find some not here,…but under Logical Functions, because here's one…that begins with IFERROR.…That's relatively new.…

And in the Windows version, there's another one here,…likely to be in the Mac version…in the next release of Excel.…Let's see how we might use these in this worksheet, here.…In row nine, also in row eight and seven,…we're checking the various numbers up above,…making comparisons month-by-month.…Let's say that whoever set it up never stopped…to think about the fact that in some cases,…some of these formulas might involve…potential dividing by zero.…For example, here's a cell right here, contains a function,…that's dividing by E4.…