# Formulas and Functions

Excel's named ranges and cell comments can help clarify formulas, but sometimes you want to put documentation into the formula itself. With the hacks in this section, you can add descriptive text to your formulas quickly and easily.

Even when you have written various formulas and functions yourself, coming back to them at a later date often requires that you follow cell references to try to figure out what the formulas are doing. It would be great if you could simply add to the end of your formula some text that wouldn't interfere with the result, but would give you the information you require at a later stage.

The problem, of course, is that the moment you add or incorporate text into part of a formula, the result will no longer be numeric and cannot be used in further calculations. Excel does, however, provide one often-overlooked function that you can use to add descriptive text to formulas or functions.

Say you have the following formula in cell A11:

```=SUM(\$A\$1:\$A\$10)*\$B\$1
```

Assume \$A\$1:\$A\$10 houses various numeric results that represent totals for a particular month, and \$B\$1 contains a percentage value that represents a tax rate. You could add some descriptive text to the formula using Excel's N function:

```=SUM(\$A\$1:\$A\$10,N("Values for April"))*\$B\$1+N("Tax Rate for April")
```

Now you can determine what the formula is being used for simply by selecting this cell and looking in the Formula bar. The N function always will return a value of 0 for any text, and so does not interfere with the formula's result in any way.