Dear fellow calcualtors, Recently I had a HD crash, so it can occur that someone does not get a reaction of mine on his message to me. I hope the experts can...
Dear fellow calculators, Please may I be a little bit proud on myself? I succeeeded in factoring the following numbers, which I got from George Lane. You...
The ability to perform the mental calculations and memorize things for competitions is enviable, but how (or do?) are these abilities used in everyday life? ...
Hi to everyone I have some queries about the recent world records and Guinness book records in mental calculation in different areas I am providing them as...
Greetings to all. With apologies for the slowness of my actions, I have now completed writing my assessment of the Mental Calculations World Championship...
Let's suppose one wants to convert a number written in base seven to base nine.. Example 2401 in base seven is 1181 in base nine. Both equal 883 in base...
Hello Every one, Thanks to all of you. One more request, Please guide me the best technic to calculate the 13th root of a 100 & 200 digit number . Thanking...
We have a new verified record for calculating the days of the week for all dates from one year (given in a random order, of course ;-) ): On 24 September 2011,...
Dear fellow calculators, A friend of mine, universitary Math teacher mailed me the list with 4 digit numbers, being the product of 2 prime numbers. Suffering...
Hi folks, I have recently completed the construction & testing of a file which generates prime factorisation problems. The file produces forty problems (in...
Thanks a lot for this list, it gives a good workout to gain number insight, so far I don`t miss the 2s ;-). Reto [Non-text portions of this message have been...
Hi, where in Philadelphia, Pa., can I go to join an in the flesh Mental Calculation group? Need some input on where practice sessions are held in Philly, if at...
Hello group members To get me some serious factor work on beginners level, I would love to have a list of semi-primes, unfortunately, the only one I stumbled...
Dear fellow calculators, If I remeber well Jerry made a suggestion for a kind of Excel file. I thought about it. This should sart with 3×3331, 5×1999,...
Hi folks. I've not seen any actviity here in the past few days, so I hope my membership link has not been broken for whatever reason. Anyway: I am now on...
My proposal is to have a record for factoring ten six digit numbers. Does anyone have a program that can generate such sets? There also is no record for...
Whenever I see a four or five digit number and have the time, I try to factor that number and the next nineteen numbers. I call such a sequence a "run." Of...
Dear fellow calculators, Hereunder you'll find my answer to Jerry Newport, as a reaction on the remarks of George Lane. Of course there is more to be said. If...
Dear fellow Calculators, I just received from Ralf Laue Leipzig the message that my new worldrecord has been recognised. It concerns 10 integer divisions of 10...
Hi All, I posted a two-part essay on extracting 13th roots of 100-digit numbers on my blog yesterday that some of you may find interesting. It starts at ...
What we are planning is something like the first PI-OLYMPICS: Competitive and international. If you can forward a competitive pi-performance, we should be glad...
Hello, One more German book, but this time it is a translation of a title already existing in English: Alex Bellos' book "Alex's Adventures in Numberland"...
good afternoon fellow calculators, Gert invited me as a guest of honour for the introduction of his new book, September 9, and was so kind to give me one of...
Gert Mittring will be a guest at "Stern TV" (German TV, channel RTL, 28 Sept 22:15). Among other things, he will extract a 98789th root from a 1.000.000 digit...
