With this month's Sudoku we'd like to share something we think is oddly interesting: Sudoku is played with the numbers 1 through 9. Almost half of these (2, 3, 5 and 7) are prime numbers, but only one of them (2) is even. Indeed, 2 is the only prime number that is even—all the others are odd. This fact accounts for why both of the following statements, which seem to contradict each other, are in fact equally valid:
- "All prime numbers are odd except one."
- "All prime numbers are odd except two."
Happy puzzle solving!