I saw this post months ago, saw it involved numbers, and passed it by. I'm horrible at any kind of math or arithmetic! But then I kept seeing this everywhere (it IS all the rage). Our Indianapolis Monthly magazine just had a big article about it. The man who invented it was an Indiana architect who didn't live long enough to see it ever catch on.
So I thought I'd give it a whirl, and I can do it!!! Even though I'm severely number challenged. It's really more about using your powers of logic. I started on the "easy" level and figured a few out. I had to cheat a few times (well, it was really more "checking" to see if I was putting in the right numbers, that's all ;-) ). Now I've moved up a step, and I have Merman hooked on it as well.
This would be great to play with while you're sitting on the beach relaxing!