180 is before 90 since, having the same "weight" (9), it comes before as a string.

1 is before 9 as a string (not 'one' before 'nine')

You should use suggestions for comments which suggest changes to the Kata, not for general questions. Without looking at your code, my assumption is that you create a vector of which increases in size as the value of the argument increases. The solution is to not do that.