[joezydeco]

I spent an hour last night working on a math homework assignment with my second-grader. The practice was adding up single digits to sums greater than 10.

The idea behind the problem (say 9+5) is to "make a 10" and then figure out the sum from the remainder. So 9+5 -> 10+4 = 14. But he didn't know which numbers routinely added up to 10. That was never memorized. The assignment was so focused on strategy and technique that it neglected the fact that the basic tools aren't there.

There's a point where you need to memorize something to make the strategy and discovery easier.