## Bedtime Math

You’ve probably heard of Read 20, a movement where parents are encouraged to read with their children at least 20 minutes a day. But Bon Crowder thinks that this shortchanges math, so she started an initiative that she calls Count 10, Read 10. While I dislike the name — math is so much more than counting — I love the sentiment.

My sons are regularly exposed to more than 10 minutes of math during daylight hours, but I’m still happy to give them another 10 minutes of math right before bed. Sometimes we use the material from Bedtime Math, but I hate the traditional problems that they serve up. I prefer instead to create new, original problems that are a bit more interesting.

This is a double-edged sword.

My kids love the problems I create, but now they’ve come to expect a new problem daily. So every night while they’re brushing their teeth, I’m mentally preparing a bedtime math lesson plan.

This has caused a lot of angst. I’m just not that creative. But two evenings ago, I crafted a problem worth sharing.

Like most five-year-olds, my kids are infatuated with the seasons. They know that the vernal equinox is usually on March 21 (they forgot, and so did I, that it’s on March 20 in 2013), they know that there is an equal amount of daylight and darkness on the equinox, and they also know that the days will continue to get longer until the summer solstice. [update – Thanks to Caitlin for the reminder about the equinox in 2013.] I asked a few questions about these facts to prime the pump, then I posed this question:

What is the difference between the number of minutes of daylight and the number of minutes of darkness today?

Alex speculated that there are two minutes more of daylight every day, so he guessed that there would be 14 more minutes of daylight. Eli made a wild-ass guess and thought it would be closer to an hour.

This led to a great discussion. If there are 12 hours of daylight on March 21 and there are approximately 15 hours of daylight on June 21 (in northern Virginia, anyway), and assuming a linear increase, then approximately 3 hours ÷ 90 days = 2 minutes of daylight are added each day. So the estimate of 14 minutes was actually pretty accurate.

As it turns out, the vernal equinox doesn’t really have an equal number of hours of daylight and darkness. There were exactly 12 hours of daylight on March 17, and there were 12 hours, 10 minutes of daylight on March 21. On March 28, there were 12 hours, 28 minutes, so the difference between that day and March 21 was actually 18 minutes.

But who cares?

The math discussion we had as a result of this question lasted at least ten minutes, so we met the goals of Count 10, Read 10. But as I said above, my kids get way more than ten minutes of math a day. Earlier today, they amused themselves for half an hour with the following problem:

Start at the 1 in the lower left corner. With each move, proceed up or to the right (never left or down). As you move, perform the operations. What path will give the maximum value when you reach the 1 in the upper right corner?

Hopefully, you’ll be able to solve this problem in less than 10 minutes before you go to bed tonight. Good luck!

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• 1. caitlin  |  March 31, 2013 at 12:10 am

Huh? We do Bedtime Math and your math problem about the equinox sounds almost identical to theirs, so not sure how much you hate it….Also they got the date right – the equinox was on the 20th this year. More important to be correct than original…

• 2. venneblock  |  March 31, 2013 at 2:32 pm

Yeah, hate was probably too strong a word. But I think there is a subtle but important difference between my problem and the Bedtime Math problems (and, for that matter, traditional textbook and state assessment problems). With most traditional problems, all of the information is given; the student is left only to figure out the operations to use. It’s the reason that textbooks and test prep courses often teach strategies like finding keywords and highlighting the numbers that appear in the problem. I find that the Bedtime Math problems have all the info included; even though they refer to other sources, they restate info. I would prefer that kids occasionally have to find the info on their own. On the other hand, my problem asks generically about how many more minutes of daylight, but they have to figure out the rest of the information that they need — that it’s a week after the equinox, that it’s 90 days between the equinox and the solstice, and that there are approximately 15 hours of daylight on the solstice. They can only solve the problem once they gather that info.

Thanks for the reminder about the equinox! My kids and I had discussed that before, and we completely forgot to include that in our discussion. I corrected the post to include that info. And I couldn’t agree with you more about th eneed to be correct!

• 3. Joshua Zucker  |  March 31, 2013 at 12:15 pm

Your grid reminds me of the game “Got It!”

If you have trouble finding a copy, let me know and I can mail you one (with included math geek pack with some extra operations to play with, too).

• 4. venneblock  |  March 31, 2013 at 2:37 pm

I don’t know it. A Google search only turned up http://nrich.maths.org/1272, which I don’t think is what you were referring to. I’d love a copy. I’ll send you my address via email.

• 5. Bon Crowder (@mathfour)  |  April 1, 2013 at 3:31 pm

Great problem, Patrick. Alas, K8 is only 3.5, so we do problems like “how many did you roll on the die.”

She does have a knack for logic, though (like in this one: http://mathfour.com/logic/logic-skills-ornery-kids-develop-them-naturally) so we get some math thinking in often.

Thanks for the plug about Count 10 Read 10. Alas, we’ve started to morph the idea into That’s Math!.

Instead of “traditional” word problems – or problems at all – we’ve set out to help parents influence kids in math. Not teach them math.

For you and me, it’s fun to create new word problems every night. But for the math phobic parents in the world, it’s downright intimidating.

So our program (which is totally free, btw) gives grownups specific stuff to say to their kids during different everyday activities. Each is geared toward the age of the child, and none of them need pencil and paper.

I’m curious to hear what you think about the new thing (and the name :D).

• 6. venneblock  |  April 3, 2013 at 9:58 am

Love the format, Bon! How much is it being used? Bedtime Math has the advantage of having a hook every day… they base their stuff on current events, or at least on cool things that kids like. As your materials are not date-specific, I’m wondering if parents are as willing to poke around till they find something they like. The subscription option should help. Let me know how it goes!

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