Looks like you're not in a test. :) I can answer your question!
So of course you probably know that anything lower than 0 is a negative number. So the variable (or unknown number in this case) is "k". K is less than or equal to -1. So, -2, -3, -4, -5, -6, and so on, would all fit this inequality.
Hope that helps! I don't want to give you the answer directly, but hope this helps you solve it.. If it doesn't, just go ahead and click "see solution" or "show example". ;)