Applying a number format to a cell doesn't change the value, but only how the value appears in the worksheet. Formatting can play a joke with you, e.g., sum of values seems incorrect because Excel displays a limited number of decimal places and their sum is not equal to the real sum.

The easiest way to enter a function into a formula is to use the Excel program's Insert Function dialog box.

Range names is a powerful Excel feature which allows you to give a symbolic name for the cell or range of cells to be later used as convenient replacement for cell/range address in formulas.

Often you'll want to insert a series of dates into a worksheet. The most efficient way to enter a series of dates doesn't require any formulas - just use Excel's AutoFill feature.

The Excel TEXT function enables you to specify numbers and date format.

If you are working with huge workbooks that contain a very large number of formulas, functions, and data, you can turn off the automatic recalculation.

There are several operators that could be used in formulas.

If you simply need to perform a calculation, you can use the Formula bar as a calculator.

Formulas can refer to cells in other worksheets-and the worksheets don't even have to be in the same workbook. Excel uses a special type of notation to handle these types of references.

You can enter nonrelative references (absolute or mixed) manually by inserting dollar signs in the appropriate positions, or you can use a handy shortcut - F4 key.