William Diebolt8,801 Points
WRONG! WRONG! WRONG!
+=, -+ etc are NOT unary operators! they are clearly infix binary operators. The video and next exercise are very wrong. Please correct this. Wasted some time, very frustrated on the simple exercise. Other people without the background will simply learn the wrong thing. These people wont even realize it until they encounter the idea again, and they will have learned the wrong thing as a FOUNDATION, maybe not remembering where. So this is a latent and pernicious bug that is kind of hard to track down. OK. I've tracked it down. PLEASE make this change.