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Comment by gklitt | Hacker News Reader

Agreed. I went to Japanese elementary school (in college now, so within the last 15 years) and didn't learn this lines method ever.

What I found greatest about the Japanese method of learning multiplication was actually the method for learning single-digit products. The Japanese use a system called "kuku" (translated, "9 by 9") which involves memorizing a rhythmic chant that goes through the entire multiplication table, with each product being concisely expressed in a few syllables. This is made possible by the various ways in which a number can be pronounced in Japanese.

I think the method is made necessary because to say the full products takes a lot of syllables in Japanese (e.g. 7x7=49 would be "nana kakeru nana wa yonjyuu-kyuu"). So perhaps it doesn't differ too much from the way you learn multiplication tables at an English-speaking school, but a cool method nonetheless.

Video here: http://www.youtube.com/watch?v=1hLyzXM53IE

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My three daughters go to doyogako (Saturday Japanese language school) which follows the standard curriculum which is why I knew. I haven't seen them use the kuku though. I'm actually working with the youngest on flashcards right now.

I've always thought it very valuable that they do math both there and at their regular US school in the hope that it will mean they aren't dramatically slowed down when math appears in a conversation like second language learners are. They certainly are crazy fluent in both languages otherwise compared to any second language learner, but I recently discovered my oldest tends to think of multiplication products in Japanese first even when in an English context. The brain is tricky :-)

It isn't that different, in my American elementary school I had to memorize the multiplication table up to 12x12. But I don't recall anything about the English language being a hindrance so your example is interesting. There doesn't seem to be that much fewer syllables in 7x7=49 in English but I'm assuming that as the numbers increase then the syllables get worse in Japanese as opposed to English? For instance, 148x385=56980?

Using your example 7 x 7 = 49

seven [2] times [1] seven [2] equals [1] forty-nine [3] = 9

七[1] 乘[1] 七[1] 如[1] 四十九 [3] = 7 (without using primary school mnemonics)

七[1] 七[1] 四十九 [3] = 5 (using primary school mnemonics)

Even at that primitive level, a change of language can give you a 23% and 45% speed-up of basic arithmetic operations, respectively.

Eh, one example isn't much for statistics. Looking at the average for 1, 2, and 3 digit numbers (ie, [0,9] * [0,9], [0,99] * [0,99], ...), using the sentence "<x> times <y> is <x*y>":

English, 1 digits: 6.5 syllables; English, 2 digits: 14.9 syllables; English, 3 digits: 25.4 syllables.

I'll let other people figure out the numbers for their own languages, but I'm guessing most languages will have similar lengths. Numbers tend to be short in any language.

A similar rote recitation exercise I recall from (a british) school was of the form '[Seven] [Seven][s] [is|are] [Forty-Nine]', of which only the 'is' is redundant, and is a single short syllable.

Yes, there are examples where the syllable discrepancy is a bit larger between English and Japanese, but I think you're right -- perhaps the syllable difference is not too big of a deal. Now that I think more about it, perhaps the actual advantage may be in the rhythmic nature of the mnemonic. By modifying syllable numbers for various products, the entire recitation gets a kind of rhythmic flow. (watch the video to see what I mean)

All I can say is that in my personal experience learning the multiplication tables in both languages around the same time, it was dramatically easier in Japanese. Perhaps the small reduction in syllables caused that, and perhaps the "rhythmification" was more responsible.

I do recall seeing a study somewhere that showed people who spoke Chinese were able to remember more numbers, ostensibly because each digit takes less syllables to speak in Chinese so the total syllables to remember in one's head is smaller.

The podcast I tangentially mentioned above talks about Soraban, and Japanese people learning Kuku:

http://www.bbc.co.uk/programmes/b01nkxkv

Isn't that the same as seven times seven equals forty-nine? In portuguese, sete vezes sete igual a quarenta e nove. Japanese doesn't look especially lengthy.

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