You can also use your 10 fingers to instantly multiply by 9s.<p>Spread out your fingers. Number them from 1 to 10, left to right (i.e. left-hand little finger = 1).<p>For 9 * 7, simply curl finger 7 downwards.<p>Now you have 6 fingers on the left, and 3 fingers on the right. Voila, 63. :-)