Today From Bedtime Math: Following Your Favorite Shark

What happens when you let a shark borrow your GPS? Find out in this wild problem from Bedtime Math!
By Laura Overdeck
Feb 24, 2015



Feb 24, 2015

What is Bedtime Math? A message from Laura: Bedtime Math is a pretty simple idea: We all know we should read to our kids at night, but what about math? My husband and I have done fun, mischief-loaded math problems with our kids at night for years, and when at age 2 our third child started hollering for his own math problem, we realized we were onto something:  In a world where so many people say, "Ewww, math!" we had created a household culture where kids don't just tolerate math, they actually seek it out. Now, every week, we'll be posting a new problem right here on Scholastic Parents!
When you watch squirrels or chipmunks run around your neighborhood, do you ever wonder exactly where they go? How many bushes, trees, and buildings do they visit? Do they stay nearby, or do they get bored and visit other streets? The answers get even more interesting for animals that swim or fly, since they can travel a lot farther. A great white shark named Lydia now has lots of fans following her every move on the Ocearch website. Scientists stuck a little gadget on her fin called a satellite tracker. No matter where she swims, that tracker sends a message to the satellite, which then marks where she is on a map. We can click on the map and see red and blue dots showing where this 2,000 pound, 14-foot-long shark is swimming, and how far she swims every few weeks. Great white sharks can be dangerous, so it feels good to chase them instead of them chasing us — and to do so from very far away!

Now see if your kids can come up with the answers to these math challenges:

Wee ones: Whose body is longer, yours or Lydia's? How "long" are you in feet?

Little kids: If the map shows a straight line of 5 blue dots for Lydia, with 100 miles between each of them, how far did she swim from the 1st to the 5th dot?  Bonus: How much longer than you is Lydia, if she's 14 feet long? (You can round your height to the nearest foot.)

Big kids: If the map tracks 20 sharks and shows 3 dots for each, how many dots are there on the map?  Bonus: If Lydia's tracker "pings" (sends a signal) every 4 hours, how many pings at most can the scientists get from 7 am to 11 pm?
Wee ones: Body length is different for everyone, but Lydia is longer than any of us!
Little kids: 400 miles, since the 5 dots have 4 spaces between them.  Bonus: Different for everyone…subtract your height in feet from 14.
Big kids: 60 dots.  Bonus: 5 pings. It's a 16-hour period, but you can get a ping at 7 am, plus the 4 more at 11 am, 3 pm, 7 pm, and 11 pm (this in math is called the "fencepost problem," when you have to count the endpoint.)

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