Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10 5/3/83; site nsc.uucp
Path: utzoo!linus!decvax!harpo!seismo!hao!menlo70!nsc!chongo
From: chongo@nsc.uucp (Curt Noll)
Newsgroups: net.math
Subject: Re: Simple Division Properties
Message-ID: <370@nsc.uucp>
Date: Tue, 30-Aug-83 17:39:53 EDT
Article-I.D.: nsc.370
Posted: Tue Aug 30 17:39:53 1983
Date-Received: Thu, 1-Sep-83 01:05:13 EDT
References: <548@uw-june>, <166@pyuxn.UUCP>, <965@utcsstat.UUCP>
Organization: National Semiconductor, Sunnyvale
Lines: 19


	>another trick, or how I learned those darn multiplication tables
	>(before then I added them up in my head. Good thing that I can
	>add fast!).
	>
	>6 times table -- 6*X, where X is even, is YX, where Y is one half
	>of X.
	>
	>laura creighton utzoo!utcsstat!laura

i assume by YX you mean Y*10+X.

i learned the 9*X (1<=X<=10) by:

9 * X = 10*(X-1) + (10-X).  one can do this on ones fingers by holding down
the digit X.  the number of fingers to the left (i.e., twards 1) is the number
of tens, and the number of fingers to the right is the number of ones.

chongo /\99/\