Apple Numbers '09 - Manual (Page 97)

Chapter 4 Working with Table Cells 97
To define a fractions format, select one or more cells, choose Fractions from the Cell
Formats pop-up menu in the format bar, and then choose a format from the submenu.
Cell Formats button
You can also use the Cells inspector.
To define a fraction format for selected cells using the Cells inspector:
1 Select the cell or cells.
2 Click Inspector in the toolbar, and then click the Cells inspector button.
3 Choose Fractions from the Cell Formats pop-up menu.
4 Choose a display format from the Accuracy pop-up menu.
Using the Numeral System Format in Table Cells
Use the numeral system format to represent numbers using the conventions of
numeral systems from base 2 to base 36. When you use the Base 2, 8, or 16 format,
you can display negative values by preceding them with a minus sign or in two’s
complement notation; negative values in all other bases are displayed using the
minus sign.
In this numeral system 100 displays like this –100 displays like this
if Minus Sign is used –100 displays like this
if Two’s-Complement
is used
Base 2 1100100 –1100100 10011100
Base 8 144 –144 634
Base 10 100 –100 –100
Base 16 64 –64 9C