That's a tough one. My sons (12 and 13) absolutely can only digest a certain amount of math in one sitting. We had a hard time with DS13 this year with his first real algebra equations (he just couldn't seem to understand doing the same thing to both sides of the equation....) We took an entire month off of his math curriculum to work ONLY on that concept. Of course, now we have a month long deficit in his actual math program and no way to catch up. I don't know that it is possible, really, for them to "get it" in math faster. And, as another poster mentioned, if they go too fast without real understanding - it will catch up with them later. However, you may want to try and entirely different approach (that is fairly inexpensive). I would suggest Life of Fred - perhaps his approach will make more sense to your children and they might actually enjoy the books. Good luck - and try not to stress! They will understand it all eventually - kids just all get there at different times.