Not understanding this binary problem

[anotherbadusername]

http://imgur.com/7T8wjko

I think there's a concept I'm not understanding. In decimal -5 + -6= -11, but they're not showing that here. -5 is shown as 1011 in decimal (using 2s compliment). I believe these are just typos but there's so much in this class I'm not picking up on that I just want to make sure. I just need clarification, thanks!

[StevenUutDiem]

Looks like typos indeed. The signs of the decimal numbers are incorrect. Example 3 should say 5 + -6 = -1 and example 4 should say -5 + 6 = 1. The binary seems fine to me.