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Minstrel
Man of Science


Registered: 03/15/05
Posts: 1,974
Loc: Hogtown
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Re: is anyone really good at doing math in their head? [Re: Montgomery26]
#8688675 - 07/27/08 03:03 PM (15 years, 9 months ago) |
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I can almost instantly determine the formula weight of any organic compound if the formula is written as CxNy and so forth, so long as it doesn't contain atoms other than carbon, hydrogen, oxygen, chlorine or nitrogen.
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DieCommie


Registered: 12/11/03
Posts: 29,258
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Re: is anyone really good at doing math in their head? [Re: Minstrel]
#8688779 - 07/27/08 03:31 PM (15 years, 9 months ago) |
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To how many sig figs?
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kotik
fuckingsuperhero


Registered: 06/29/04
Posts: 3,531
Last seen: 4 years, 4 months
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Re: is anyone really good at doing math in their head? [Re: DieCommie]
#8700963 - 07/30/08 05:14 AM (15 years, 9 months ago) |
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I'm surprised I'm the first one to mention Vedic math, otherwise known as "magic" math.
Vedic math is based on 16 principles (sutras). It still uses math, but there are lots of shortcuts.
For example, multiple any number by 9, and the digits of the solution will also add up to 9 (or a multiple of 9).
e.g. 5x9 = 45. 4+5=9. and: 73x9 = 657. 6+5+7 = 18. (and 1+8=9)
So instead of actually doing the traditional concept of math in your head, it's a bit different; more like translating a language I guess. Some people confuse it with numerology, which it is not.
There's another method for adding times very easily, not sure which sutra it is (or if it has its sutra).
basically when adding times, say 1:27 and 5:44, you have to convert the times to seconds, or at least do some mental math to deal with the 60/100 denominator difference... however there is a "magic time" number with a constant value of 40 that takes that entire step out. Instead of converting the time, you just bunch the numbers together, add, and then add 40. Hard to explain, easy to illustrate:
instead of this process: 1:27 = (1x60)+27 = 60+27 = 87 5:44 = (5x60)+44 = 300+44 = 344 87 + 344 = 431 431/60 = 7 r11 7:11
you do this: 1:27 = 127 5:44 = 544 127 + 544 = 671 671 + 40 = 711 711 = 7:11
admittedly, each of those have 5 steps... but clearly the second version was much easier. 3 steps involved removing or adding a colon, with only 2 actual steps with very simple addition. This would be at most a 2-step mental process.
The typical (western) method can be done mentally as well, but it takes a bit longer, since you have to do a variety of mental calculations.
The sutras get into complex math, such as square roots, cubic roots, long division, etc. It's not limited to simple equations by any means.
Just some very small examples of vedic math opposed to western math. I firmly believe that if I was taught both methods in school, I would have ended up keeping an active interest in math, instead of having it beaten out of me with long, boring equations. I'll stop before a rant ensues.
-------------------- No statements made in any post or message by myself should be construed to mean that I am now, or have ever been, participating in or considering participation in any activities in violation of any local, state, or federal laws. All posts are works of fiction.
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delta9
Active Ingredient


Registered: 10/28/04
Posts: 5,390
Loc: California
Last seen: 13 years, 6 months
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Re: is anyone really good at doing math in their head? [Re: kotik]
#8701068 - 07/30/08 06:52 AM (15 years, 9 months ago) |
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Quote:
kotik said: I'm surprised I'm the first one to mention Vedic math, otherwise known as "magic" math.
Vedic math is based on 16 principles (sutras). It still uses math, but there are lots of shortcuts.
For example, multiple any number by 9, and the digits of the solution will also add up to 9 (or a multiple of 9).
e.g. 5x9 = 45. 4+5=9. and: 73x9 = 657. 6+5+7 = 18. (and 1+8=9)
How does this help you multiply faster?
The easiest way in base 10 to multiply N by 9 more quickly is to multiply N by 10 and then subtract N. The same goes for multiplying N by 11 only you add N at the end.
-------------------- delta9
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deCypher



Registered: 02/10/08
Posts: 56,232
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Re: is anyone really good at doing math in their head? [Re: Epigallo]
#8703754 - 07/30/08 06:29 PM (15 years, 9 months ago) |
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Pssh... doing math in your head is overrated. It's all about seeing how many digits of pi you can memorize instead.
-------------------- We are all in the gutter, but some of us are looking at the stars.
 
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delta9
Active Ingredient


Registered: 10/28/04
Posts: 5,390
Loc: California
Last seen: 13 years, 6 months
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Re: is anyone really good at doing math in their head? [Re: deCypher]
#8705682 - 07/31/08 01:24 AM (15 years, 9 months ago) |
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Quote:
3.141592653589793238462643383279502884197169399375105820974944592307816406286208998628034825342117067982148086513282306647093844609550582231725359408128481117450284102701938521105559644622948954930381964428810975665933446128475648233786783165271201909145648566923460348610454326648213393607260249141273724587006606315588174881520920962829254091715364367892590360011330530548820466521384146951941511609433057270365759591953092186117381932611793105118548074462379962749567351885752724891227938183011949129833673362440656643086021394946395224737190702179860943702770539217176293176752384674818467669405132000568127145263560827785771342757789609173637178721468440901224953430146549585371050792279689258923542019956112129021960864034418159813629774771309960518707211349999998372978049951059731732816096318595024459455346908302642522308253344685035261931188171010003137838752886587533208381420617177669147303598253490428755468731159562863882353787593751957781857780532171226806613001927876611195909216420198938095257201065485863278865936153381827968230301952035301852968995773622599413891249721775283479131515574857242454150695950829533116861727855889075098381754637464939319255060400927701671139009848824012858361603563707660104710181942955596198946767837449448255379774726847104047534646208046684259069491293313677028989152104752162056966024058038150193511253382430035587640247496473263914199272604269922796782354781636009341721641219924586315030286182974555706749838505494588586926995690927210797509302955321165344987202755960236480665499119881834797753566369807426542527862551818417574672890977772793800081647060016145249192173217214772350141441973568548161361157352552133475741849468438523323907394143334547762416862518983569485562099219222184272550254256887671790494601653466804988627232791786085784383827967976681454100953883786360950680064225125205117392984896084128488626945604241965285022210661186306744278622039194945047123713786960956364371917287467764657573962413890865832645995813390478027590099465764078951269468398352595709825822620522489407726719478268482601476990902640136394437455305068203496252451749399651431429809190659250937221696461515709858387410597885959772975498930161753928468138268683868942774155991855925245953959431049972524680845987273644695848653836736222626099124608051243884390451244136549762780797715691435997700129616089441694868555848406353422072225828488648158456028506016842739452267467678895252138522549954666727823986456596116354886230577456498035593634568174324112515076069479451096596094025228879710893145669136867228748940560101503308617928680920874760917824938589009714909675985261365549781893129784821682998948722658804857564014270477555132379641451523746234364542858444795265867821051141354735739523113427166102135969536231442952484937187110145765403590279934403742007310578539062198387447808478489683321445713868751943506430218453191048481005370614680674919278191197939952061419663428754440643745123718192179998391015919561814675142691239748940907186494231961567945208095146550225231603881930142093762137855956638937787083039069792077346722182562599661501421503068038447734549202605414665925201497442850732518666002132434088190710486331734649651453905796268561005508106658796998163574736384052571459102897064140110971206280439039759515677157700420337869936007230558763176359421873125147120532928191826186125867321579198414848829164470609575270695722091756711672291098169091528017350671274858322287183520935396572512108357915136988209144421006751033467110314126711136990865851639831501970165151168517143765761835155650884909989859982387345528331635507647918535893226185489632132933089857064204675259070915481416549859461637180270981994309924488957571282890592323326097299712084433573265489382391193259746366730583604142813883032038249037589852437441702913276561809377344403070746921120191302033038019762110110044929321516084244485963766983895228684783123552658213144957685726243344189303968642624341077322697802807318915441101044682325271620105265227211166039666557309254711055785376346682065310989652691862056476931257058635662018558100729360659876486117910453348850346113657686753249441668039626579787718556084552965412665408530614344431858676975145661406800700237877659134401712749470420562230538994561314071127000407854733269939081454664645880797270826683063432858785698305235808933065757406795457163775254202114955761581400250126228594130216471550979259230990796547376125517656751357517829666454779174501129961489030463994713296210734043751895735961458901938971311179042978285647503203198691514028708085990480109412147221317947647772622414254854540332157185306142288137585043063321751829798662237172159160771669254748738986654949450114654062843366393790039769265672146385306736096571209180763832716641627488880078692560290228472104031721186082041900042296617119637792133757511495950156604963186294726547364252308177036751590673502350728354056704038674351362222477158915049530984448933309634087807693259939780541934144737744184263129860809988868741326047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