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andrwleong (November 30, 1999 at 12:00 am)
these are proper maths skills, used by memory champions
weirdofromplanetmars (November 30, 1999 at 12:00 am)
man ...this is old! wtf is up with the clothes!wtf!
aiwomew2 (November 30, 1999 at 12:00 am)
dude... this IS an old video
toasterder (November 30, 1999 at 12:00 am)
lets see, lets a = 100. let b = 5, what is (a-b)^2?a^2 - 2ab + b^2, 2ab = 2ab = 10 a, and a is always 10so from lets say a-b = 95, the difference from here will be 5 already, and another 5 more because 2(b) a, well figure the rest yourself because its easy, he merely used an algebriac identity for multiplication. that actually used the effect of 10^2lets try 69 x 71 = (a + b)(a - b) = a^2 - b^2, and you can break a^2 = (c - d)^2, and addition is simple... what you learnt in school.
omgitskher (November 30, 1999 at 12:00 am)
LOL you're still just adding it up.
torende (November 30, 1999 at 12:00 am)
check out the kid in the pink shirt @ 7:13he's like: dude, get out of my personal space!
CaptainAshMorrigan (November 30, 1999 at 12:00 am)
i agree, theyre pretty time consuming to work with at first, its a foreign concept of visualing multiple numbers, for some people. it gets faster with practise.
123w4rp1g321 (November 30, 1999 at 12:00 am)
Yeh they can be used in ALL sums I worded that wrong. What I actually meant was that it is impratical to use it in most circumstances.
CaptainAshMorrigan (November 30, 1999 at 12:00 am)
123w4rp1g321,It appears to work for all sums. I thought id test it a little.So we know 95, and 96, work.. He explains it wrong however.lets take 89 for example. Thats NEGETIVE 11 away from 100, so minus 11 = 78, + two 00's on the end. 7800, + 11x11 (121) = 7921.Now for OVER 100.101 x 101 = 10201, we know this.101, is positive 1 from 100, so + 1 to 102 = 102(00), and 1x1 = 1, so thats 10201.Get it? it appears to work for all, i dont understand how the kid got the Square Root, however, brb
123w4rp1g321 (November 30, 1999 at 12:00 am)
Yeh I don't see what I was getting at there. Oh well I was young. |
