Math mom

I saw this link on the Boston Globe website about a mom who blogs about how there is math everywhere, even in the everyday lives of moms and kids. So I'm going to add my geeky math mom story that just happened this weekend.

So Tom and I were tag team babysitting our two nieces with the boys last weekend. Our new little family of six had lunch at McDonald's. Cheapos that we are, they each had water to drink, in a kids cup, with a plastic lid and a straw, in other words: they were all identical. Knowing that my boys love to punch the buttons that indicate "DIET" or "RB" or "OTHER", it dawned on me I had the PERFECT math problem for them.

Me: Hey kids, how can tell whose cup is whose when you four all have the same cup drinking the same thing?

Three of them had blank looks on their faces. Tobey was quite intrigued by the challenge.

Tobey: We can tie the straw paper around the straw!
Me: Well, yeah, but there's four of you.

[More thinking...]

Me: Hint - Look at the caps of your cups (which, in their case, had two buttons each, DIET and OTHER).

[More thinking...]

Tobey: Emily and I can push our buttons and Rachel and Eli can leave their buttons!

To spare you more gory details, we got them all (not just Tobey) about how they can make 4 unique combinations of ON/OFF buttons to distinguish their four drinks.

I love it when math is just so appropriately practical! I never once had to say the word "math"!

Then I pushed one step too far and showed them my cup cap, which had DIET, RB, TEA, COLA and OTHER on it and asked how many different people can distinguish their cups if they all had 5 buttons. While I fully believed Tobey would have tried to figure it all out, Tom said, maybe it was a little advanced for them. And we went back to eating our french fries.

But I did, tonight, just get back from leading one of the activities at our school's Math Night. It was really fun. And seriously, I'm not that much of a math geek. Yes, I appreciate math, but as a kid (and now still as an adult) sometimes got really annoyed at the math brainteasers my dad used to put in front of me, especially when they're just for "fun" (whose definition of "fun" are we talking about?). And here I am being part of the very institution that I hated: a whole night of math brain teasers.

Anyway, one of the activities one of the parents did was called the Popcorn Problem, but I like to call it the Happy Meal problem (McDonald's again!) because to me it seems a little more relevant, even though the math is all the same.

Suppose the current promotion at McDonald's advertises 6 different Happy Meal toys. Assuming at any given time/day/restaurant, you have an equal chance of getting any of the 6 Happy Meal toys, how many Happy Meals do you think you need to buy before you get all 6 of the Happy Meal toys?

I thought the way the problem was presented was fun. The way he tallied up the whole groups experiments in a histogram was really effective. It reminded me why teaching is so fun.

And that's coming from not so geeky a math mom.