Change the number format of datasheet cells or chart items
- To format cells, click View Datasheet
if you need to display the datasheet, and then select the cells you want to change.
How?
To format a chart item, such as data labels or an axis, click the chart item you want to change.
How?
- Click the button for the format you want.
To select another format, click Number on the Format menu.
To display Click Commas to separate thousands Comma Style 
Currency symbol Currency Style 
Numbers as percentages of 100 Percent Style 
Fewer digits after the decimal point Decrease Decimal 
More digits after the decimal point Increase Decimal 