Once a math teacher....

I caught a ride to Weyburn for a funeral today.  Ruth and I were commenting that 20-30 years ago, when we had a big gathering, it was likely a wedding.  However, now most of the big gatherings we attend tend to be funerals.  This was a big gathering, and it was wonderful to be able to visit and share with so many people.

The car was full - Ruth and Walter in the front, and three of us in the back.  The middle back position had a child, I'm not going to use his name, as things posted on the internet can come back to haunt you years later, but let's say he was under eight years old.  He likes to play cribbage on my phone, so I changed the settings and showed him how to count the points for himself.  He enjoyed that; he could find the pairs and when there were three in a row, but had trouble figuring out which combinations would add up to 15.  However, that took up most of the time on the way to Weyburn (a generous hour's drive).

On the way back to Regina, I played a "game" with him.  I counted out my spare change in my wallet, and borrowed a few more coins from Ruth until I had 15 coins - all nickels and dimes.  I was determined that I would teach him that 9+6=15 and 10+5=15; as well as the commutative property of addition, so that 6+9 is the same as 9+6 and also equals 15.

Anyway, to say it took awhile would be an understatement.  Because 15 coins is a lot, and we couldn't lose any, we used my hat to hold the coins, plus a hand.  I'd have him count how many coins in my hand - and there would always be either 5, 6, 9 or 10.  Then he had to guess how many coins were left in my hat.  For example, he'd count 6 coins in my hand, and guess there were 5 coins in my hat.  So then we'd count how many coins were in my hat - and there were 9 of them.  Then, with him watching, I'd switch, and have 9 coins in my hand... how many coins are in the hat?  And he'd guess 12 or some other random number.  We did this for about 45 minutes!

Finally, I told him that if he got it right ten times in a row, he could keep the coins!  This provided a great incentive.  He'd get it right two or three times, then would do a random guess again, and we'd start over.  We arrived in Regina before he finally got the idea.  And then it was, well duh!  If there are 6 coins in your hand, there are 9 in the hat.  And if there are 9 in your hand, there has to be 6 in the hat.  And the same with 5 and 10.  And what had been an exciting game, all of a sudden had become boring!

Let's see if he can remember when I see him tomorrow.