RAY: Go out and get yourself 16 matchsticks. You're going to use the matchsticks to make the following Roman numeral sequence. One, then two matchsticks to make a plus sign. Plus Roman numeral two. Plus Roman numeral three. Plus Roman numeral four, which is not "IV," but, in this case, "IIII."

[For the Car Talk Puzzler Psychic Friends Network, that equation would be: I + II + III + IIII ]

TOM: If you add this up, one plus two plus three plus four, it adds up to 10.

RAY: Right. The question is, can you move one matchstick, without removing it, still using them all -- and make that equal to four?

[ Car Talk Puzzler ]