Thank's for your reply, Scott. I see. It is the proof that the Quarter Squares-Rule produces the result ab. Do you see also how one can derive the identity by...
Fans of the world's greatest ever calendar-calculating double act might enjoy this film. http://www.cbsnews.com/sections/i_video/main500251.shtml?id=2405880n...
It is good to see he is now living with a bit more autonomy than in his youth. Emmanuël rob221b <rob221b@...> a écrit : Fans of the world's greatest...
Hmm. this sounds like a homework question... anyway, a hint to get you started you have ab = ((a + b)^2 - a^2 - b^2)/2 hence ab = ((a + b)^2)/2 - (a^2 + b^2)/2...
Unlike the previous posts, my proof is algebra-free. Just stare at this picture long enough and the rule will appear to you "stereogram-style". Arrange 4...
A I expected, the picture got messed up. I would upload a picture-file to the group, but that feature seems to have been disabled. I place here instead: ...
Hello Rob! Yes, this is it. You could also say 4ab = (a+b)^2 - (a-b)^2 (0) And (a+b)^2 = a^2 + 2ab + b^2 (1) is the 1. Binomische Formel (a-b)^2 = a^2 - 2ab...
Hi everybody! Some time ago I've discovered the world of Mental Calculation. I've bought the book of Bill Handley "Speed Mathematics" but I remained...
f> Now I've bought the book on the Trachtenberg systhem because I've f> read some nice commments on this book. The Idea are very nice. Please, sell it back. ...
Oleg Stepanov
olegstepanov@...
Feb 12, 2007 8:58 am
2172
... Hello Oleg! I also began mental calculation and know some of the books you bought. I have also a book from Ronald W. Doerfler which also denotes general ...
... Also I began writing a book on Mental Calculation myself. I want to cumulate many formulas, simplifications and principles and write it in this book....
Please tell me when you release your book. Can you recommend some books? Best regards Michael ... Datum: Sun, 18 Feb 2007 08:17:31 -0000 Von: "peterschreyfogl"...
George Lane's book "Mind Games - Amazing Mental Arithmetic Tricks Made Easy" comes highly recommended! Andy ... From: Dr. Michael Paridon <dr.m.paridon@...>...
Dear Oleg, thanks for reply. You are telling me that the book of tratchenberg is not good, right? (sorry for my english, I speak italian. Wich book or web do...
... on 18 ... Hello, Congrats to Yusnier. There is no answer to this message but i am curious. What kind of record is it ? Written record ? Best wishes....
Hi Andy, Many thanks indeed for the recommendation; it's very gratifying to know that a fellow expert calculator views my book with such regard. However, I...
... Hi Frederico! I am also discovering the world of mental calculation as you do and find it rather interesting. I know these two books you mentioned. A book...
Hi Everybody! Can anyone tell me, what is Gamm's method to raise a 2-digit number to the nth power? METHOD 1 (a+b)^2 = a^2 + 2ab + b^2 but (a+b)^20 is a little...
b> Hi Everybody! b> Can anyone tell me, what is Gamm's method to raise a 2-digit number b> to the nth power? Mnemonic. Sincerely Yours, Oleg Stepanov. ...
b> He just memorized the numbers? Correct. JUST! Sincerely Yours, Oleg Stepanov. http://stepanov.lk.net/...
Oleg Stepanov
olegstepanov@...
Mar 2, 2007 10:30 am
2184
Yes indeed; Emmanuël bluecodemail123 <bluecodemail123@...> a écrit : He just memorized the numbers? Quel est le contraire d'un ouistiti ? Reponse : un...
Hello, Willem Bouman kindly sent me an outline of his lectures on mental arithmetic at the University of Leiden with permission to post it to the group: ...
Some time ago there was a discussion on this board about "How to compute mentally" S ( J ) = J mod 19 for any year J. You will remember that this number is...
thanks arunmangal@... ... From: mnempi To: MentalCalculation@yahoogroups.com Sent: Monday, April 16, 2007 9:06 PM Subject: [Mental Calculation]...
arun mangal
arunmangal@...
Apr 16, 2007 9:03 pm
2190
And please note that this way of dealing with centuries and years contradicts the generally upheld opinion that the Christian era for the Venerable Bede and...
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