Put a little thought into today's mentalfloss.com Think Thursday Brain Game challenge and you'll come up with the right answer. Good luck!

When counting in Roman numerals from
1 to 2500, which Roman numeral "digit"
(I, V, X, L, C, D, M) is used in the fewest numbers?

Here is the SOLUTION. 

SOLUTION:

"D" (500) is used the fewest times.

Only 1101 of the Roman numerals from 1-2500 use a "D."

By comparison, "I" appears at least once in 2000 of the Roman numerals from 1 to 2500. Here's the rest of the list:
V - 1250
X - 2050
L - 1250
C - 2050
D - 1101
M - 1601

Thanks for playing!