[Newbie]Changing display modes on Laptops

[newbie@XFree86.Org (Roger W.Brown)]

  Hi,

      On my desktop machine, I can change display modes using
  a combination of the Ctrl/Alt/Nuneric-Plus or
  Ctrl/Alt/Numeric-Minus keys; however, my new laptop does
  not have a numeric keypad.

  Is there an alternative way to change the display mode ?

  Roger