Numeric values are usually more than just numbers. They often represent dollar values, dates, percentages, or some other value. You can select the format type that appears as a real value in the Format Cells dialog box. To narrow the list of formats, first select a category in the Category list, then specify the number of decimal places. The default number of decimal places is two.
Excel lets you display numeric values in many ways. Formatting a number means changing the way it is displayed. You can format the number 500 to look like currency, in which case it's displayed as $500.00. You can even specify as many decimal places as you want to display.
You can choose from four currency styles:
Currency with negative ...