On 16/03/2005, at 5:57, various people wrote on:
Subject: Re: Poll: the sum(7,9) Reply-To: How to use Revolution <use-revolution@lists.runrev.com>
It's this: How do you mentally process simple addition/subtraction facts? What actually happens in your brain to elicit 16 when you hear 7+9? (for example)
It depends a bit on how complex the question. My response to "7 9 +" was initially the second of those originally suggested by Mark - pattern recognition, probably a direct consequence of his third option, rote learning at school. The same certainly happens instantly for numbers where the sum is less than 13 and very fast for others. When the numbers get larger, I use accumulated pattern-bits to break down the problem and derive an answer, which actually seems to involve an approximation on most parts of the number then fixing the details in any unconsidered digits. If it is "difficult" or I am tired then concrete methods start to move in to deal with it, involving visualising changing numbers.
However, the later question, "17 9 -" (seriously folks, over 30 years my thinking really has shifted to the point where RPN is as easy as and "more sensible" than infix) caught my attention. The answer came straight away but I managed to rerun the question immediately in my head and think I got some glimpse of what happened, insofar as one can believe introspection. It went something like " 9 is one less than 10 and I see 17 so the answer is 8". Bang. Nothing more I noticed (I barely caught the "and I see 17" but it had to be there) and in retrospect I am not quite sure I would think of it quite that way, but it seems to work.
cheers David _______________________________________________ use-revolution mailing list use-revolution@lists.runrev.com http://lists.runrev.com/mailman/listinfo/use-revolution
