One of the things I love most about educational technology and social media is when something comes across my feed that yields a really rich mathematical task. Amazon's status update one day gave me just that and I shared it, along with my mathematical addition. In today's Solver Blog, I'd like to tell you how this problem went over with my class.

My students laughed out loud when they read the Problem of the Day that began class, which is always a good start! What's more, they were interested (curious) to know what the answer was (even better!). As usual, I asked for estimates first and got a range of answers that were all over the place (also fairly typical). Pause for a moment and answer that for yourself before reading on: what is your estimate for how many lamps Amazon sold?

We used Polya's problem solving process and my students told me they needed to know some stuff before figuring out the answer. Specifically, they told me they needed to know both the height of the lamp and the height of Mt. Everest. Thanks to #edtech of various kinds, both pieces of information was readily available.

Amazon's site itself told us that the "full size" Leg Lamp from A Christmas Story was 45" tall (and sells for $149.99 as of today's sale price) and Google informed us that the elevation of Mt. Everest was 29,029 feet. Now we were ready to make a plan.

My students preferred working from "the big number" down so they decided to take the height of Mt. Everest, convert that to inches, then divide by 45 to see how many lamps "fit".

29,029 ft x 12 in/ft = 348,348 inches

348,348 / 45 = a little over 7,741 lamps!

The answer was verified by a couple of other methods (and checked with cell phone calculators to ensure no silly arithmetic errors had happened along the way). Most everyone was surprised by the number (the closest estimate that day was 10,000) and all found the problem fun and engaging.

I extended the idea by asking them to come up with similar catchy / mathy ways to state something. Here's what I gave them as an example:

If I had a quarter for each minute I've been alive, they would weigh more than a Orca whale!

hmmm, somehow putting it into that context makes me feel old! :-) How about you? What's your problem statement? Share them with me; I'd love to hear them (and use them in my class).

The Solver Blog

Author: Dr. Diana S. Perdue