Sunday, November 20, 2011

How tall is Yertle the Turtle?

That ego-maniacal Yertle, proclaiming himself king of all that he sees, calls for a stack of 500 turtles to sit upon.
And now Yertle the Turtle was perched up so high,
he could see forty miles from his throne in the sky

So tell me: how tall is each turtle?  Assume the earth is a sphere with radius 4000 mi, that Yertle and the reset of the turtles are a uniform height, and that Yertle's eyes are on the top of his head.  The first correct solution (posted as a comment) will earn a cool drawing of the solver on top of Yertle.

Tuesday, November 8, 2011

Flip the Sign

Katie Cunningham, a NBCT friend of mine at an alternative school in Washington helped her students make a music video to aid their solving of inequalities. Warning: you may have it stuck in your head for the rest of the day.

Saturday, November 5, 2011

Million-dollar division problem

When pressed, I'll reluctantly admit to be a sucker for reality shows.  While catching up on The Amazing Race, I came across this scenario.

Brian and Ericka are presented with a choice: Construct 12 hookahs or weigh out $500,000 worth of gold using the current price per ounce.  They choose the latter (wouldn't you?).  They find themselves in a room with a lot of gold, a scale, and a screen telling them the up-to-the-minute price: $934.75 per ounce.

The first thing they need to figure out is what to do with the numbers $500,000 and $934.75.  Fortunately they are able to answer this (another team had a harder time), but now they're stuck with a long division problem, something with which former Miss America doesn't feel confident: "My American education has dumbed me down to use a calculator for everything."  Plus, the rate just changed: $941.25/oz.

Now, take a moment to appreciate that a long-division problem is standing between them and their goal of winning $1 million.  Ericka had a point: how many students are graduating high school with competency in arithmetic?  I'm guilty of allowing too much calculator use in my classroom as well, having uttered justifications like, "It lets students stay focused on the higher-order concepts..."  This may be true and appropriate at times, but my students would have benefited from more arithmetic thrown into the mix.

Have your students work against the clock, giving them a new divisor every so often.

Poor Brian and Ericka eventually gave up - is that what your students would do?