My observation of points at which even very smart people fall off the "math train" k-12: - Fractions - Factoring So yeah, I'd say great care is warranted in

My observation of points at which even very smart people fall off the "math train" k-12: - Fractions - Factoring So yeah, I'd say great care is warranted in teaching kids fractions. Screw that up and there's a good chance you've lost them for life.