Season's Greetings, Math Club! With the holidays on the horizon, a famous song leads Pete and Noah to talk about strategies for adding up long sequences of numbers. Come join the fun, and learn how a young Carl Gauss may (or may not) have done it. And if you're up for a challenge, we even "sum it up" with a special holiday puzzle for you to try.

• Brian Hayes's article in American Scientist

• Submit your puzzle solution here