For example, when it comes to using the math racks and making equal equations where you show that 7+8=10+5, my son was able to do it, but I'm not sure that he was full grasping that you're manipulating the math racks (adding 3 to the top bar and simultaneously taking 3 off the bottom one to get 10 and 5). Instead, he was adding 7+8, then building 15. Does that make sense? His method works in the cases where he'd memorized the math facts, but not when he didn't already know the answer. It's clear that he needs more practice doing that, but it's now marked as "completed".
Yes, I had this experience, too. My DS would figure out how to complete the level, without understanding the principle being taught. It worked out, though. Weeks later, it would become clear that he had mentally pieced it all together. It has been mentioned elsewhere on this forum: sometimes moving up to a harder principle will help the details of the easier principle come into focus.
Also, Zen Scanner is right, the game spirals back on concepts as needed. And things pop up just for review, too.
