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Topic: Pi Mnemonics
Replies: 6   Last Post: Feb 19, 1996 5:03 PM

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John Conway

Posts: 2,238
Registered: 12/3/04
Re: Mnemonics for real numbers automatically [was: Pi Mnemonics]
Posted: Feb 19, 1996 2:52 PM
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On Mon, 19 Feb 1996, Antreas P. Hatzipolakis wrote:

> Allan Wechsler <> wrote:

> >I suppose dozens of people remember Gardner' column that mentioned
> >several pi mnemonics.


Does anyone actually USE these mnemonics? Since they depend on the
exact choice of words, rather than their individual meanings, it would
seem to me that anyone who does so is VERY liable to make a mistake.

My own technique, for what it's worth, is to go through the digits
one wants to memorize, trying to make them "rhyme" or "alliterate".
For the first few digits of pi, this is quite easy:-

_ _ _
3 point 1415 9265 35
^ ^
_ _ _ _ _ _ __
8979 3238 4626 4338 3279
'' ''^^ ^^ ''''

This gets us very nicely to 30 digits, after which we group pairs of 3's
for the next 30 digits:

. _ _ __ _ _ _ . _ .
502 884 197 169 399 375 105 820 974 944
^ ^ ^ ^
(the hard-to-remember first and fourth blocks here are very similar)

and then the absolutely wonderful 10-digit block that contains all
10 digits (digits 61-70) and which I obviously can't rhyme or
59230 78164

but then it's very nice (15 places with three near-repeated 4-blocks)
_ _ _ _
0628 6208 998 6280
^^ ^^ ^^
and three reasonable 5-blocks take us up to 100 places:

.. _ .._
34825 34211 70679.
^ ^

I have often maintained that any person of normal intelligence
can memorize 50 places in half-an-hour, and often been challenged by
people who think THEY won't be able to, and have then promptly proved
them wrong. On such occasions, they are usually easily persuaded to
go on up to 100 places in the next half-hour.

Anyone who does this should note that the initial process of
"getting them in" is quite easy; but that the digits won't then
"stick" for a long time unless one recites them a dozen or more times
in the first day, half-a-dozen times per day thereafter for about a
week, a few times a week for the next month or so, and every now
and then thereafter. [Keep a "crib", so that whenever you find you've
forgotten some digits, you can quickly reinsert them!]

John Conway

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