This is a good read on how to commit concepts to long-term memory and building skills. I think there is a typo in the article though; there is a point that say

This is a good read on how to commit concepts to long-term memory and building skills. I think there is a typo in the article though; there is a point that says: > work out the problem by computing 6 × 5 = 5 + 5 + 5 + 5 + 5 + 5 = 30 (or 6 + 6 + 6 + 6 + 6 = 21) The second parenthetical statement should be 30, unless I’m missing something?