jwcolby
jwcolby at colbyconsulting.com
Mon Sep 19 12:01:44 CDT 2011
http://en.wikipedia.org/wiki/Trachtenberg_system John W. Colby www.ColbyConsulting.com On 9/19/2011 11:34 AM, David McAfee wrote: > Don't forget the 9's hand trick: > > Put down the finger of the number that you are multiplying with 9. > > for example, 9x4 > > Hold you hands out with the backs of your hands facing you. > put down your left index finger (or 4th from the left) > > The number of fingers to the left of the finger (3) that is down is your > first digit, those to the right (6) add up to your right digit. > > It's so awesome to watch children light up when they learn something new. > > :) > > David > > > My kids loved showing their friends this trick. > > On Mon, Sep 19, 2011 at 1:55 AM, Arthur Fuller<fuller.artful at gmail.com>wrote: > >> Can they multiply yet? There are some cool things about multiplication. I >> like the elevens especially. 11*11=121. 11*11*11=12121, and so on. The >> nines >> are cool, too: take the digits in any multiple of nine and they add up to >> 9: >> 18, 27. 36. 45, etc. >> >> Arthur >> _______________________________________________ >> dba-SQLServer mailing list >> dba-SQLServer at databaseadvisors.com >> http://databaseadvisors.com/mailman/listinfo/dba-sqlserver >> http://www.databaseadvisors.com >> >> > _______________________________________________ > dba-SQLServer mailing list > dba-SQLServer at databaseadvisors.com > http://databaseadvisors.com/mailman/listinfo/dba-sqlserver > http://www.databaseadvisors.com > >