By using Microsoft Excel, I found that:- 10001 = 73 x 137 9999 = 101 x 99 Â Therefore followed what had been discussed by Andie on 1001 & 999, we can use...
Further to the methods as discussed regarding the finding of prime factors, there is a very useful method to determine divisibility of dividend by a divisor,...
Talking about 9s and 1s reminds me of a nice web page I saw recently about prime numbers. Perhaps some overlap?: http://home.egge.net/~savory/maths1.htm Mike ...
Thank Michael for the link for divisibility. Lately I was interested in calculating cube root, any one knows any links or method for calculating cube root? I...
Hello calculators, Here is the very incomplete rating for the French Federation of Mental Calculations. For the moment i just try to understand what would be...
Hiya! Â The idea of ranking/rating mental calculators in the style of martial arts rather than that of chess is very interesting; I understand the game of...
Yes, that is indeed true - and, as I have already said for myself, memory is used to increase the speed at which people can 'calculate' by storing heaps of...
Hello George, Â I am attentive with your comments. Â "The idea of ranking/rating mental calculators in the style of martial arts rather than that of chess is...
Hello George, You want comments: well you get them!!!!!!!!!!!! For me a real calculator is versatile, in this way I understand the wide variety of operations...
Hello Willem, "it is an interesting matter, but I wonder what the use is for memorising prime numbers to 100.000 or even less." < < My problem is: 3*90679=...
Bonjour Jean Eric, A little correction please: your problem is not 3*90679, as you give the answer yourself. I presume you want to know if 90679 is a prime...
Hi Willem, and hello to everyone else too of course. Â Yep, no mistake there - you've made plenty of comments, and that's precisely the reason I invited them....
Dear calculator friends, Did you also receive a message in which is promised you could be faster than a calculator (machine?????????) High Speed Vedic Maths is...
Hi George, for the good order: ceativity is meant as a help for finding solutions. As an example: I found a lot of creativity in your book "Mind games". ...
Hello Willem, in fact i know that 90679 is a prime number. But concerning the number "272037", my question was: how a calculator can be sure this number is a...
There is, of course, also the simple matter of the digits of 272,037 adding to a total of 21. As this is a multiple of three, then the whole number is also a...
Hello Andrew, Yes, indeed, you're completely right, thanks for your remark. Regards, Willem ... Van: Andy Robertshaw Aan: MentalCalculation@yahoogroups.com ...
Dear calculating friends, As far as I can see most skills have already been 'maxed out' (dominated) by other mental calculators. For example: Addition and...
Dear Jsh, You should have heard me laughing, I still do!!!! I am honoured a little bit too much: it is factorising a 16 digit number composed by 4 consecutive...
Dear Willem Bouman, I am still startled. I wonder if you would be so kind as to give me an example of this performance and how long it would usually take as...
Hi folks, Â I'm not sure I'd say I've mastered huge division problems, but integer divisions aren't really too tough to handle. Remainders - the integer...
Dear Jsh, To start: the idea came from my good friend Robert Fountain, who gave me the wonderful nick name "William Flash, King of the Primes". In the...
Hello, has anyone registered for the memoriad in Istanbul yet ? What do you think about it ? Do you know that they want us to give the results of the...
Hello Jan, Please clarify when adding and multiplying does this force you to do so from left to right if so then that does sound quite challenging. From Jsh ...
Dear anyone in the know, Okay I'm going to swallow my pride and ask. I'm sure you're all aware of the basic square root algorithm as seen in wikipedia and the...
Dear Jan, I do not know who told you that you would have no chance to correct your answers in calendar category. Without seeing any software simulation how...
Dear Jan, I do not know who told you that you would have no chance to correct your answers in calendar category. Without seeing any software simulation how...
Hi all,  Firstly an apology. In my message yesterday I may inadvertantly have given the impression of belittling Wiilem Bouman's ability to name the four...
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