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Thu Nov 22, 2012, 10:30 AM

How those from Japan multiply - as in maths.

Check this out.

http://www.iltasanomat.fi/tiede/art-1288518199598.html

5 replies, 967 views

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Reply How those from Japan multiply - as in maths. (Original post)
dipsydoodle Nov 2012 OP
BlueJazz Nov 2012 #1
OffWithTheirHeads Nov 2012 #2
DetlefK Nov 2012 #3
Warpy Nov 2012 #4
dipsydoodle Nov 2012 #5

Response to dipsydoodle (Original post)

Thu Nov 22, 2012, 10:49 AM

1. I've seen this before and the process seems to be the slowest way to do math ever invented.

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Response to dipsydoodle (Original post)

Thu Nov 22, 2012, 10:52 AM

2. Recd just for your sig line!

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Response to dipsydoodle (Original post)

Thu Nov 22, 2012, 11:24 AM

3. Nice. How about 909 x 2876?

1. Uneven number of digits.
2. A zero.
3. Multiple intermediary results >10.

Let's see how he fares against the conventional method now.

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Response to dipsydoodle (Original post)

Thu Nov 22, 2012, 12:05 PM

4. I've seen this before

but it gets horribly cumbersome with numbers over 5.

It is useful as a demonstration for kids who understand things visually instead of understanding abstractions.

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Response to Warpy (Reply #4)

Thu Nov 22, 2012, 12:36 PM

5. It seems to be an illustration

to demonstrate the manner in which how those who "see" the solution to long multiplication by simply visualising the building blocks in their mind are able to do so. My younger brother could do that when he was seven and his teachers at the time couldn't make out what on earth he was doing whenever he just wrote an answer left to right with no workings. When they asked he explained in a manner which conveyed "why are you asking me such silly questions."

I was also never able to understand how my father could provide any root of any number , within reason, after just a short delay while he thought about it. Turned out that in his teens he'd learned the log and anti-log tables.

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