#1**0 **

Hint: How many permutations of three numbers{-1, 0, 1} can you arrange so that their SUM is always zero?

3! = {-1, 0, 1} | {-1, 1, 0} | {0, -1, 1} | {0, 1, -1} | {1, -1, 0} | {1, 0, -1} (total: 6). But since you have unlimited supply of these tiles, then {0, 0, 0} would also qualify?? Makes sense?

Guest Jul 8, 2018