Khan hasnt helped me at all and ive been using it all year and that is how my teacher grades me so i havent been doing so great. We started this new thing called "aleks" Which is also not the best thing i have ever used for math or anything.
At first when my friends told me about it i was thinking (oh another lame o math game) but when i tried it it was actually fun! Although member ship costs some it actually helps you answer more questions. In fact the teachers at our school who teach k-2 grade use it to teach their students. (im not k-2 if you were thinking that)