I agree that "The 12 Days of Christmas" makes for a fun toy-problem domain. Not convinced you could have squeezed that into your 20 minutes, but there will be other opportunities!
+//.~ ; <\ 1+ i. 12 12 22 30 36 40 42 42 40 36 30 22 12 On Fri, Dec 16, 2011 at 3:34 PM, Roger Hui <[email protected]>wrote: > > NB. I wanted to tell them the story of Gauss as a schoolboy > > NB. summing the numbers from 1 to 100 in no time flat. > > > > +/ 1 2 3 4 5 > > 15 > > 1 2 3 4 5 + 5 4 3 2 1 > > 6 6 6 6 6 > > 5 * 6 % 2 > > 15 > > 100 * 101 % 2 > > 5050 > > At the kids' school today they sang "The 12 days of Christmas", and I > realized that I missed a golden (ring) opportunity the other day. > > > > On Wed, Dec 14, 2011 at 11:05 AM, Roger Hui <[email protected] > >wrote: > > > I got myself invited to talk to a grade 7 math class at my kids' school. > > I was given 20 minutes. The following is a record of the session of my > > talk, with my comments added afterwards. > > > > 2 + 3 > > 5 > > 2 - 3 > > _1 > > 2 * 3 > > 6 > > 2 % 3 > > 0.666667 > > 2 % 5 > > 0.4 > > > > NB. I was told that the talk I had was "too advanced", so my goal > > NB. was to get across one main simple idea, the following one. > > > > 2 3 4 + 8 1 7 > > 10 4 11 > > > > NB. a student thought that 2 3 4 was 234, and gave 1052 > > NB. as the expected answer. > > > > 234 + 817 > > 1051 > > > > 2 3 4 - 8 1 7 > > _6 2 _3 > > 2 3 4 * 8 1 7 > > 16 3 28 > > > > NB. Some students seem quite smart, so I slipped in "insert". > > > > +/ 2 3 4 > > 9 > > */ 2 3 4 > > 24 > > 2+3+4 > > 9 > > > > NB. a student asked about order of operations > > > > 2 + 4 * 3 > > 14 > > 2 * 4 + 3 > > 14 > > (2 * 4) + 3 > > 11 > > > > NB. I wanted to tell them the story of Gauss as a schoolboy > > NB. summing the numbers from 1 to 100 in no time flat. > > > > +/ 1 2 3 4 5 > > 15 > > 1 2 3 4 5 + 5 4 3 2 1 > > 6 6 6 6 6 > > 5 * 6 % 2 > > 15 > > 100 * 101 % 2 > > 5050 > > 1 2 3 4 ... + 100 99 98 ... > > |spelling error > > | 1 2 3 4 ... + 100 99 98 ... > > | ^ > > > > NB. a student asked about exponentiation > > > > 2 ^ 3 > > 8 > > 4 ^ 3 > > 64 > > 2 4 ^ 3 2 > > 8 16 > > > > 2 ^ 123 > > 1.06338e37 > > > > NB. A student ask where he can get the software. Another asked "PC or > > Mac?" > > > > At the end, the teacher suggested I go talk to the high school (8-12) > > classes. > > > > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
