Math Monday makes its return. This puzzle is worth some effort, because even when you figure out what the answer should be, you have to figure out what the answer is. I hope you find it challenging. (For what it's worth, the Roman numerals in this post's title are no hint whatsoever. Really.) Good luck!

What's the next number in this sequence?

1, 0, 11, -12,... ?

Here is the SOLUTION.

THE SOLUTION:

-90.

The numbers are the smallest integers that can be spoken in one syllable ("one"), two syllables ("ze-ro"), three syllables ("e-lev-en"), and four syllables ("ne-ga-tive-twelve"). The smallest number that can be spoken in five syllables is "ne-ga-tive-nine-ty."