I'm fulfilling a legal obligation to comment on Khan Academy, it's in the math teaching website code. If you somehow haven't heard, there's this dude on the East Coast who has a lot of people kissing his feet over an endless supply of videos he's made covering problem solving for almost any kind of subject you can imagine. He started with math videos and the largest chunk cover math topics. Specifically, he will walk you through random examples of nearly any topic. Brilliant! Genius! You might say. Well, go sit through one.
At the end, yes, you will probably be better at solving a particular kind of problem. But, there's zero context. After working an example on limits, does that mean you understand a limit? Could you pick out a real world model of one? Do you like limits more now? Does it make you more interested in math? I would say doubtful.
Now, these videos were brought up more than once during staff development this year. Thankfully, not as the savior of all that is math, but referenced as a resource as my district pushes a big focus on technology.
There is one and only one scenario I would suggest a student watch these, if they can find one that will help them solve a homework problem. And even then, I would hesitate severely and put a caveat on the suggestion ("it's extremely dry, but you might see something").
Never ever are these things getting shown in class. Never ever will we have a class project emulating them. In my opinion, if your answer to lesson planning a particular chapter is to let Khan Academy (or any other tutorial video series see: bad high school physics classes) do most of the talking, you're doing it wrong.
Side note, it also reinforces an interesting problem in math, that kids get upset if they try something that doesn't work. I make errors from time to time in my explanations that I catch eventually, but guaranteed when I catch it there's at least one agigated sigh in the room as the erasers come out. I'm not alone:
I know my students take the same approach when solving puzzles, whether it’s video games, mobile games, crosswords, or sudoku. They dive right in and tinker. So why, when faced with a physics problem, do many students suddenly freeze-up if they can’t see the whole solution right from the outset? How do we show students it’s OK to dive right in, go down blind alleys, hit deadends, backtrack, and try again?
An experiment I'm going to put on the shelf for a proper time, has anyone tried asking a student who hates math why? Perhaps root out the causes? Would the results be consistent? I envision an exit survey from time to time "how are you and math this week?" "what scared you this week?" "was there a time you and math were bff? what changed?" I don't know. I hope I could get something out of it more than "I'm not good at it. It's confusing."