Author Archives: Mr. Chase

Who Am I?

Posted on by
2

I’m reposting this great puzzle, found originally at The Math Less Traveled blog. Enjoy!

 

There are five true and five false statements about the secret number. Each pair of statements contains one true and one false statement. Find the trues, find the falses, and find the number.

1a. I have 2 digits
1b. I am even

2a. I contain a “7”
2b. I am prime

3a. I am the product of two consecutive odd integers
3b. I am one more than a perfect square

4a. I am divisible by 11
4b. I am one more than a perfect cube

5a. I am a perfect square
5b. I have 3 digits

15 degree triangle

Posted on by
Reply

Check out this fun problem at the math challenges blog. I picked it in honor of what we’re doing in Precalculus right now, since it has a trigonometric flavor. Don’t look at the answer until you’ve tried it! In fact, after looking at the answer, I found I had done it a different way. So let your creativity run wild. I’d love to see your proof, if you figure it out. And if you want a hint, come see me or email me.

Should Calculus be on Top?

Posted on by
2

Paul Lockhart’s A Mathematician’s Lament.  My response to his essay is posted here, if you haven’t checked it out. Here are some more thoughts on Math Education that pick up where we left off.

I think we agree that we need a structured curriculum that gets students from point A to point B. Of course, our curriculum needs to allow for exploration, discovery, and fun, as Paul Lockhart says. But still, in order to prepare people for the real world, we need to take them from point A to point B. But if we’re honest, only 2% of students (I’m being generous) will be in fields where anything beyond Algebra is required of them. And usually, by point B we mean Calculus or something like that (in RM’s case…it may mean Multivariable Calculus/Diff.Eq. or HL Math). We just accept that point B is always Calculus. But most students will never use Calculus directly. This is a tough thing to come to grips with: It’s absolutely true that 98%++ of students will never apply directly the math we teach. What do you think of that?

Here’s a 3 minute talk by Arthur Benjamin, who suggests we change “point B” to be Statistics, not Calculus, as a response to this very dilemma.

Arthur Benjamin is a professor at Harvey Mudd College and an all-around cool guy. You might enjoy his other, more light-hearted TED talk (performance, really) in which he does “Mathemagic,” found here.

Einstein’s Puzzle (Answer)

Posted on by
1

Okay, don’t read any further unless you’ve already tried the puzzle. It’s a classic logic puzzle and can be solved by the standard grid-technique, like commentors suggested. I did the same thing, and I got this answer:

The German owns the fish.

Did you get that too? Here’s the thing: It’s technically not correct, according to a few sources I found. Some people say the correct answer to this problem is “there’s not enough information; the fish isn’t even mentioned in the listed facts.” I’m not sure what I think, but it gives some food for thought. Consider the following new problem and you’ll see why:
Who is the American?
(Fact 1) Winston and Paul are of two different nationalities
(Fact 2) Paul is Canadian.
What do you think? Would you say “Winston” or would you say “Winston could be anything (except Canadian) given the facts”? If you say “Winston” then you’re actually assuming a third fact: One of them is an American.
In the case of Einstein’s Puzzle, we technically need a 16th fact: One of them owns a fish.
So what do you think? Those of us who solved the puzzle in the classic logic-problem grid-solution way simply assumed that fact and got on with our lives. But what do you think? Do you think we can assume that someone owns the fish even though it’s technically not a “fact?” It’s an interesting issue–perhaps just a linguistic one. Let me know what you think.