Math Teachers at Play #5 is up at Let’s Play Math! It’s organized by topic, with pictures and neat quotations thrown in for good measure. And as usual, it is full of interesting posts!

Speaking of Carnivals, apparently the Carnival of Mathematics was just hibernating and it will reappear next week. At least, that’s the rumor, where “rumor” means I read it on jd2718.

And speaking of reading things, after reading Keith Raskin’s comment I headed over to Natural Blogarithms to look for Pythagorean Triple stuff, and I was immediately distracted by the following puzzle:

The four numbers A, B, A+B and A-B are all prime. The sum of these four numbers is

A) Even

B) Divisible by 3

C) Divisible by 5

D) Divisible by 7

E) Prime(from the 2002 AMC 10/12B #15).

I quickly convinced myself of one answer, then decided there was a misprint and talked to Batman about it at work, and then we he realized that exactly one of the possible answers was correct. At that point the problem seemed a lot more interesting.

If you need something a little more lighthearted this Friday afternoon, here’s the 1-20 roll call from Sesame Street.