Re: Myth about mathematicians and mental arithmetic

"John Coleman" <jcoleman@xxxxxxxxxxxxxx> wrote in message
news:1168259328.798128.123530@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
[snip]

I find that I am slower at such things than I could be since I value
accuracy over speed. Unless the problem is completely trivial like 25 x
7, I find that I usually double check. Thus in your example I saw what
the answer was in about 3 seconds but then it took another 2-3 seconds
before I reached a point where I was comfortable with the answer.

It took me roughly 2 seconds to calculate the above mentally and I am
considered "slow" by many standards.

Ultimately I think it depends on practice. When I was in the army back in
1993, I and 4 other mathematicians were put in charge of the platoon's kiosk.
This was similar to a mini-market for the new soldiers.

I was put on the window, doing the sales. In the beginning, I could hardly
calculate 2-3 item totals together. After roughly a week at the sales window,
I could manage multiple items, in the order of 10-15 different kinds, doing
the complete linear combination sum in 5-10 seconds. (3 packs of potato chips
+ 2 packs of ciggies + 4 coffees + 5 croisants, etc).

After I left the kiosk in the end of the month, I gradually became slower
again.

An interesting aspect of such calculations for me is that certain numbers are
"nicer" in my mind and I have less problems calculating combos of them. For
example, my mind considers certain multiplications easier, for reasons
unknown. Usually calculations which avoid long carries tend to be calculated
faster.

[snip]
-John Coleman
--
I.N. Galidakis
http://ioannis.virtualcomposer2000.com/

.

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