Rather than memorize how to multiply a small number of permutations of numbers, learn in the general case how to multiply small numbers quickly.
Few people who memorized the 12x12 grid and then moved on can quickly say that 13 times 7 is (70+21=91).
Caching the products of small factors will develop naturally as a result of training the general skill.
Splitting 13 7 into (10+3)7 is very much the kind of thinking as using the 'easy' multiplication problems like 9X. The idea was to focus on showing how addition and multiplication fit together.
But if there's an 'easy' way to get 3*7, shorter than 7+7+7 and less brute-force than memorizing it, please do tell!
Although my 8-year-old son likes his teacher, he is frequently bored at school. He attends a high quality suburban public school in the United States. He has a lot of traits in common with LessWrong readers, and we would like advice for what he can do to counter his boredom. Many of you must have found grade school more or less tedious. What were your coping strategies?