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At risk to be downvoted to death, I have to say that the new way of multiplication is actually _better_ than the old one, at least for kids starting to learn ho
by mynegation 16y ago
At risk to be downvoted to death, I have to say that the new way of multiplication is actually _better_ than the old one, at least for kids starting to learn how to multiply.
All the new multiplication algorithm does is makes implicit additions explicit, so that you do not have to keep carry-over digit in memory. 144 is 120+24 and 720 is 600+120. Sure it trains your short memory, but we are talking about 7yr olds here. Once kid feels comfortable s/he will naturally move to the "old" way of multiplication.
And anyway... It is easy to nitpick on something we understand very well, but how about the topic? What would you do to make math more enjoyable in the classroom? I know what worked for me personally and that was not classroom drilling of multiplication, divisions, and stupid problems with two pipes filling the pool at different speeds.
What made me love math are Marin Gardner's books and other fun math books. It was much more interesting to solve crimes with what I later came to know as propositional logic, or cutting tori in different ways.
- Splatchar 16y agoI think you've nailed it by considering the carry-overs. With the new method there's less opportunity for error. The old way, there are two sets of carry digits: those arising in the initial multiplying, then more in the final adding up (though not in the example given). Sometimes I would try to remember them; sometimes I would write them down in various places; frequently I forgot or muddled them up somehow. Another benefit is: the new way gives you a sense of the magnitude of the final answer more quickly. Approximations are useful. Contrast with the old method which begins by multiplying the least significant digits.