Dr. Timm stood at the door as the last of the kids filed into his math class. As the bell rang, he shut the door and began writing on the board:

22-120-212 111-1-112-221 10-120-110-120-200-201 1-121-121-12-1-200 120-112 202-22-12 1-111-12-200-100-10-1-112 20-110-1-21?

When he finished writing, he turned to his students. “Okay, here is your challenge for the semester. I will pay one hundred dollars to the first student who can answer what I have on the board.â€?

The class was immediately abuzz, and Dr. Timm knew the challenge was still on their minds even after he had started his lesson. Ten minutes into class a hand went up.

“Yes, Ryan?â€?

“I have the answers to the challenge,â€? Ryan replied.

“By all means, enlighten us.â€?

Ryan read from his work, “Negative three-ten, negative two-twenty three, negative seven-forty-one…â€?

“No, no, and no,â€? Dr. Timm said. “Keep trying.â€?

“But that’s what I got too,â€? Rachel chimed in.

Dr. Timm laughed, “You didn’t think I’d make it that easy, did you?â€?