Similarly, an old accountant's trick: If something doesn't balance, try dividing the error by three. If it IS divisible by three, it's probably a couple transposed digits. For example: 12345 - 12435 = -90, which is divisible by three. Also, to tell if a number is divisible by three, add the digits. If the sum is divisible by three, so is the original number. Harold On Thu, 7 Jun 2001 16:54:01 -0400 Thomas McGahee writes: > I'm too busy now to tackle the problem (end of school, > and as a teacher I am inundated with work!), but > I offer this observation: The sum of the digits of any > multiple of nine will always add up to nine. If you get > a multi-digit answer, then add those digits as well. > > For example, the digits in 2736 add up to 18. The digits > in 18 add up to 9, so 2736 is an integer multiple of 9. > > Fr. Tom Mcgahee > > ----- Original Message ----- > From: Scott Dattalo > To: > Sent: Thursday, June 07, 2001 3:55 PM > Subject: [pic]: 9 > > > > Let's turn all of this amateur mathematical rambling about > repeating 9's > into > > something useful: > > > > What's the most efficient PIC code (execution time) to determine > if a > number is > > evenly divisible by 9? > > > > I think it can be done in 12 instructions, right Dmitry. > > > > Scott > > > > -- > > http://www.piclist.com hint: The list server can filter out > subtopics > > (like ads or off topics) for you. See > http://www.piclist.com/#topics > > > > > > -- > http://www.piclist.com hint: The list server can filter out > subtopics > (like ads or off topics) for you. See http://www.piclist.com/#topics > > FCC Rules Online at http://hallikainen.com/FccRules Lighting control for theatre and television at http://www.dovesystems.com ________________________________________________________________ GET INTERNET ACCESS FROM JUNO! Juno offers FREE or PREMIUM Internet access for less! Join Juno today! For your FREE software, visit: http://dl.www.juno.com/get/tagj. -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.