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I think it's basically the same method, but if not enjoy Isaac Send a noteboard - 29/02/2012 09:16:21 PM
X, followed by a zero, X added to results. 25 X 11. 25, followed by zero, 250, added by itself, 250+25 = 275. Excellent!

38 X 11 = 380+38 = 418! Just gotta be good at adding fast ;)


Mostly you just have to be good at knowing how to partition calculations in your head, which is mostly practice. You don't for instance go through the long procedure for multiplication for something like 1008x1009, you break as 1000+8*1000+9 and it becomes 1000²+ 8x1000+9*1000+8*9 or 1,017,072, which is a hell of lot faster usually, even then punching it into a calculator especially if it's not switched on in front of you. These aren't really 'tricks', math is basically nothing but tricks, and much of physics is learning them and getting practiced at dragging them out and adapting them.
The intuitive mind is a sacred gift and the rational mind is a faithful servant. We have created a society that honors the servant and has forgotten the gift.
- Albert Einstein
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Does anybody know this math trick? Dark Knight - 29/02/2012 07:29:58 PM 755 Views
Sure, it's an artifact of base 10 Isaac - 29/02/2012 08:24:18 PM 549 Views
Your own fault for doing lots of math. Joel - 29/02/2012 08:37:39 PM 614 Views
More my fault for having a algebra textbook that obsessed with abnormal base calculations Isaac - 29/02/2012 09:19:15 PM 608 Views
I think I had one like that one year. Joel - 02/03/2012 04:16:26 AM 756 Views
Your method for 11 might be even quicker! Dark Knight - 29/02/2012 08:46:44 PM 439 Views
I think it's basically the same method, but if not enjoy Isaac - 29/02/2012 09:16:21 PM 421 Views
That's what I've always used. Nate - 29/02/2012 09:24:05 PM 437 Views
Squares and factoring are also your friend. Joel - 02/03/2012 03:56:08 AM 567 Views
Yes: I was taught it in school aged 11 or 12. *NM* Tim - 29/02/2012 11:33:22 PM 180 Views
That is wayyyyy more complicated than 10x+x. But if it works for you, I am happy. *NM* Ghavrel - 01/03/2012 07:16:40 AM 198 Views
Not really Dark Knight - 01/03/2012 04:24:20 PM 404 Views
That's, uh... the same thing. Ghavrel - 01/03/2012 08:38:03 PM 378 Views
Again, it's the doing it in your head thing Dark Knight - 01/03/2012 10:27:01 PM 499 Views
Yes. It's called multiplication. *NM* Dreaded Anomaly - 02/03/2012 12:40:20 AM 245 Views
Har har har. Why even comment? *NM* Dark Knight - 02/03/2012 05:15:05 AM 181 Views
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