I've been going through the Khan Academy math exercises to see what math kids are learning. www.khanacademy.org While I am very impressed with the Khan Academy & its exercises, I am appalled by the time & effort in teaching fractions -- especially "mixed fractions". I realize that this is not the Khan Academy's fault -- KA is merely providing exercises to teach for the tests that the kids will have to pass. But who on Earth actually uses this stuff & why do we torture kids this way? No wonder people hate math. --- I think that the ability to do rudimentary programming is far more valuable to every kid than the ability to handle "mixed fractions". In fact, the ability to sum/difference numerical fractions at all is simply not terribly relevant. Ditto for greatest common divisor and least common multiple. (Truth time: when was the last time you used "least common multiple", except on a test?) Yes, there is a time for "number theory" & gcd's, but it should come considerably later, in conjunction with algebra & groups, rather than with basic arithmetic. Yes, there is a place for summing fractions: when simplifying algebraic expressions, but not in basic arithmetic. --- The hours in every kid's life are valuable, and the hours in every teacher's day are even more valuable. Why do we want to waste these hours teaching them skills that bore them out of their minds, and that they will never use? If there is an educational crisis, it would appear to be caused by clueless adults.