Every math student knows that special feeling when your professor speeds through a complex proof, then casually drops "...and the rest is left as an exercise for the reader." Just like this cool dude staring into the distance, we're all mentally calculating whether to cry, laugh, or drop the class! The infamous "exercise for the reader" is basically academic-speak for "figure it out yourself because I'm either too lazy to finish or I want to watch you suffer." Next time you're stuck on one of these "simple exercises," remember you're part of a proud tradition of confused students everywhere!