This Week From Bedtime Math: Way Larger Than Life

The quickest way to make a cake better is simple: Stack another one on top of it!
By Laura Overdeck
Nov 05, 2013



This Week From Bedtime Math: Way Larger Than Life

Nov 05, 2013

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!


That big, yellow piece of LEGO with the little blue piece on top looks a little bumpier than usual, doesn't it? Well, it's actually a giant cake, with upside-down cupcakes as the bumps, and in the bottom right corner you can see the teeny real LEGO that was used as a model. When we build bigger versions of small objects, we have to go bigger by the same number of times in every direction. So if that cake is 10 times as wide as the LEGO pieces, it also needs to be 10 times as deep back to front, and 10 times as tall. The result won't hold just 10 of the little LEGO pieces – it will hold 10 times 10 times 10 of them, or 1,000 of them! It's 1,000 times as big. And just as the LEGO got scaled up to make the cake, we scale things down, too, like toy dolls, cars or trucks that look like the real thing but are much smaller. Of course, whether we scale things up or down, it works out best if you can then eat the result.


Now that you're mind is stretched in all directions, try challenging your kids to these fun math problems.


Wee ones: If we have a real yellow LEGO piece, a blue LEGO piece, a giant yellow cake piece and a giant blue piece, how many “pieces” of LEGO do we have in the photo?


Little kids: If you can line up 12 yellow LEGO pieces along the bottom edge of the cake and you have 1 sitting there already, how many more yellow pieces do you need?  Bonus: If you also get enough blue pieces to make 12 little copies of the cake, how many teeny LEGO do you have in total (including the starting pieces shown)?


Big kids: If you decided to make just a cupcake-sized LEGO piece that was twice as wide, twice as deep and twice as tall, how many times as big as the original LEGO piece is the cupcake (i.e., how many LEGO can you fit inside that space?)  Bonus: What if it's 3 times as big in each direction?




Wee ones: 4 pieces of LEGO.

Little kids: 11 more pieces.  Bonus: 24 pieces.

Big kids: 8 times as big.  Bonus: 27 times as big.

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