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BGonline.org Forums
Square root, ...cube root .. mmm fun !!!
Posted By: neilkaz In Response To: Is BGO an Elitist Society? (Jason Lee)
Date: Friday, 12 December 2008, at 3:39 a.m.
Is there any trick algorithm for cube roots ?
About 15 years ago, when training on the trading floor in Philly with my former company, a couple traders introduced me to a guy known as "Rain Man" since he was so very gifted at mental math. Anyhow.. we looked at each other chatted a bit, and my colleagues wanted some action.
We settled on a cube root contest. We had to take the cube root of a 6 digit digit number totally in our heads without calculator (duh) or pencil or paper and we had 5 minutes to do so and at the conclusion of 5 minutes we had to write down our answer to two decimal places and the one closest to the correct answer was the winner. Just in case someone got lucky we decided to make it 2 outta 3.
Well..my opp was very gifted at this..perhaps (duh) I was set up...I dunno..but he only missed by 0.02 !! Unfortunately for him, I did some mental math extropolation/interpolation or what ever it is called and also managed to do an estimated calculation cubing my answer and nailed it spot on. Score ..Neil 1, and a MUCH less pompous Rain Man (who was muttering that no one has ever done what I just did) 0.
Next number...Rain Man again impressed everyone but is off by .02 again while I nailed it..and a lot of money changed hands. I recall that my answer to the last one was 77.68 and trust me, while this may seem like bragging...I needed all 5 minutes and no time for a guesstimation cubing of my answer check..(time ran out and I was .."WTF OK seems close enuf")
This was LOTS of work..so are there any tricks for cube roots ? Maybe there are..maybe my opp had some method but was good enough to nail it to 2 decimal places. Anyhow..when, after the last one, as me and my colleagues had half the trading floor handing over 20's, 50's and 100's, and I told him that I intopolated(he asked HFT did I do this) and said "how fucking hard is it to cube(estimate) 77.7 and 77.6 and then interpolate anyhow ?" he simply lowered his head and skulked away, knowing that he was OWNED.
OMG..my poor tired old head is exhausted just thinking about that... and the fact that no one (as all told me) had ever come close to beating that dude in mental math..be it speed or accuracy.
Sorry for bragging...and don't expect me to teach this ..'cuz I can't explain it.
.. neilkaz ..
PS I won't talk about what happened when the shits in my former company tried to set me up vs the 15th best chess player in the US.. at speed chess. (I told them my time handicap was too much..but they insisted)
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