MATLAB always keeps track of numbers to double precision regardless of the output format. To alter the display of numbers, use format. The argument short gives five digits (the default) and long fifteen digits; a second argument of e to either switches to floating-point.
Further, format hex gives hexadecimal, format + gives signs only, format bank uses dollars and cents, and format rat uses ratios of small integers as approximations.
Finally, format compact and format loose can be set independantly of all the other formatting, and supress or allow, respectively, extra linefeeds in output.