don steward
mathematics teaching 10 ~ 16

Saturday, 12 February 2011


choose any number (circle it) and cross out the other numbers in the same row and column as this
then do this again
and do it a third time
then put a circle round the remaining number and add up the four numbers

do this a couple of times
what happens?
why does it happen?

[ idea from Mathematics in School, January 1989 ]

No comments: