Select one or more cells.

Click Inspector in the toolbar and click the Table button.

In the Table inspector, click Format.

Choose Custom from the Cell Format pop-up menu.

The custom format window opens.

From the Type pop-up menu, choose Number & Text.

Define your number format by dragging the (blue) elements from the Number & Text Elements box into the format field above the box.

• Integers:  
  Add this element when you want to format digits to the left of a decimal point. See Defining the Integers Element of a Custom Number Format for more information.
• Currency:  
  Add this element to display a currency symbol. To identify the symbol you want to use, add the Currency element and click its disclosure triangle and choose a symbol.
• Decimals:  
  Add this element to format how decimal digits are displayed. See Defining the Decimals Element of a Custom Number Format for more information.
• Spaces:  
  Use this element to control the amount of space displayed between elements. To specify the amount of space, add the Spaces element, click its disclosure triangle, and then choose an option. Normal adds a standard space, Wide adds an em space, and Narrow adds a sixth of an em space. You can add more than one Spaces element to the format field with these options, but only one of the Spaces elements can be Flexible; this option left-aligns the elements that precede it and right-aligns elements that follow it.
• Scale:  
  Use this element to size the display value of a number. For example, you can display values over 100 as number of hundreds (1000 displays as 10). See Defining the Scale of a Custom Number Format for more information.

To display predefined text before or after any element, place an insertion point in the format field and then type your text. You can click any element and use the Left Arrow and Right Arrow keys to place the insertion point.

To delete an element in the field, select it and then press Delete.

To move the element around in the field, drag it.

In the Name field, type a name for your number format.

Custom format names are listed in the Cell Formats pop-up menu in the Format pane of the Table inspector.

Click OK to save your number format and apply it to the selected cells.