Last Friday Blinkdagger announced a winner for MMM #8. Here's MMM #9:
Consider all of the 6-digit numbers that one can construct using each of the digits between 1 and 6 inclusively exactly one time each. 123456 is such a number as is 346125. 112345 is not such a number since 1 is repeated and 6 is not used.
How many of these 6-digit numbers are divisible by 8?
While you may use a computer program to verify your answer, show how to solve the problem without use of a computer.
We have a winner for this seventh contest. Congratulations, Brent Yorgey! I'm delighted that Brent, of Math Less Traveled, won this one because Brent gives so much to students and readers of his blog. Brent - Enjoy your $25 gift certificate from our kind sponsor for this contest, the Art of Problem Solving.
Click here to see Brent's solution, two of them actually.
I've been wanting for some time to incorporate mathematical equations into my blog posts. What I've done up to now is to use this nice web site that Brent from Math Less Traveled pointed me to. You enter a LaTeX expression and the web-site creates an image which you then copy over to your web server and reference from your blog post. This system works great if you only need a small number of images. As an example, I used it to typeset the problem in Monday Math Madness #7.
A while ago I received an email out of the blue from Texas Instruments (TI). One of their marketing people discovered this blog and offered to send me a TI-Nspire calculator to review. I quickly accepted, after all, who would turn down a free fancy calculator, right? Once I received the calculator I realized that this was no ordinary calculator; it was a visual Math learning system. I did nothing with it for a couple of months until I finally realized that I was not the best person to review it as it would take me quite a bit of time and effort to learn and appreciate its power. Sure, I could read the manual and run some demos but I didn't think that would give me enough experience to write a very in-depth review.
In discussing my challenge with TI, I learned of some teachers who were successfully using the TI-Nspire in the classroom. One person in particular, Eric Butterbaugh, was teaching Math in Harlem, New York. It occurred to us in that conversation that readers of this blog would appreciate hearing about Mr. Butterbaugh's success with the Ti-Nspire system. I created some interview questions and received back the interview you're about to read.
Tonight is your last chance to get your Monday Math Madness #7 submission in.