I think that's what you get with unsupervised learning.
Tricks only get you so far, you can't do 6+7 on fingers or 7·7 as (4+3)(4+3) (I had a huge problem with this one, too many numbers to track). So you fail. And when you fail, you memorize the problematic cases and go on with tricks based on those.
And yes, it's completely incomprehensible for people who learned the pencil-and-paper algorithms and think that those are the end of the world.
Tricks only get you so far, you can't do 6+7 on fingers or 7·7 as (4+3)(4+3) (I had a huge problem with this one, too many numbers to track). So you fail. And when you fail, you memorize the problematic cases and go on with tricks based on those.
And yes, it's completely incomprehensible for people who learned the pencil-and-paper algorithms and think that those are the end of the world.