Originally Posted by lulu
How about a thorough understanding why to turn the second fraction upside down when multiplying, instead of just being taught to do it ? I think many kids of this age, including gifted ones, just blindly accept what to do, without understanding the inverse of multiplication concept. I'm not suggesting your DS wouldn't get this - just that many may not.

Yes, he understands the concept. I guess I have been assuming he's not really more advanced than the other kids in this class.