Myth: Multiplication table weakens computing skills

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Myth

Memorizing multiplication table deprives one of computing skills. Like kids using calculators, those who memorize the multiplication table with SuperMemo will become less numerate (i.e. less fluent in their calculation skills)

Fact

The basic 9x9 multiplication table is the cornerstone of all calculation on paper and in mind. Memories are best formed by the use of numbers, not by cramming the table at school (see: Toxic memory). However, memorizing the 20x20 multiplication table is also a good way of training basic multiplication skills. It is hardly possible to actually memorize the 20x20 table. Intuitively, most students do it the right way by using the combination of their familiar 9x9 table, and their adding skills. For example, 14*16 is remembered as 10*14+6*14=140+6*10+6*4=140+60+24=224. This means that the student uses (1) a simple decomposition, (2) zero-shifting rule, (3) the 9x9 table once (to figure out that 4*6=24) and then (4) addition (to add the resulting three numbers). In contrast to the myth, all students who learned the 20x20 multiplication table report a dramatic increase in their multiplication skills. Alas, there is relatively very little carry over to division skills. These require additional learning material and slightly more complex skills. Those who need to multiply often, my try to learn larger multiplication tables and use them as a training ground for calculations. Unless cramming is used, training with multiplication tables increases numeracy

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