12345679 * 18 = 222222222 123456789 * 18 = 2222222202 See the difference (hint: there is no '8' in the first equation) -Randie > From i@CHEETAH.SPOTS.AB.CA Thu Oct 2 08:58:47 1997 > MIME-Version: 1.0 > Date: Thu, 2 Oct 1997 09:57:55 -0600 > From: Shane Nelson > Subject: Re: How do you test Math Routines? > To: PICLIST@MITVMA.MIT.EDU > > On Fri, 3 Oct 1997, Ray Gardiner wrote: > > > A quick and dirty check is as follows... > > This a trick, which i believe relates back to the abacus days where > > you multiply 12345679 by any two numbers adding to 9 and you will get > > a repeating digit. > > > > ie: 12345679 * 18 = 222222222 and > > 12345679 * 27 = 333333333 etc... > > I just had to try it and... > > 123456789 * 18 = 2222222202 > ... > > Unless you only want the first 8 Most Significant Digitis in > which case you were correct... > > > .scn >