There's a large gap between 'fast enough to be a decent substitute for a LUT' and 'needs paper'. There's no doubt that one needs to be ABLE to add 7+7+7, but I don't think that each repetition on the path to memorizing 3*7=21 needs to involve it.
Does it take longer to ad 7+7+7 than to say "Seven times three is twenty-one" and "three times seven is twenty-one"?
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?