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  • Hello. I'm Professor Von Schmohawk and welcome to Why U.

  • This series of lectures is an introduction to Algebra.

  • But before we discuss Algebra

  • we should start by taking a closer look at the things we call numbers.

  • In even the earliest cultures

  • understanding and communicating quantities has been essential to everyday life.

  • Anthropologists tell us that even the most primitive stone-age cultures

  • had some concept ofnumber”.

  • However, early number systems were much more limited than today's base-10 number system.

  • Life was simple back then.

  • We didn't need names for exact quantities.

  • If you knew that there was a herd of gazelles nearby

  • it didn't matter exactly how many gazelles were in the herd

  • or exactly how many miles away they were.

  • What was important was that there were a lot of gazelles and they were just over the hill.

  • Even recently, certain Australian aboriginal tribes counted only to two

  • with any number larger than two called "much" or "many".

  • South American Indians along the Amazon had names for numbers up to six

  • although three was called "two-one", four was "two-two" and so on.

  • Bushmen of South Africa had a similar way of naming quantities

  • but stopped at ten because the names became too long.

  • This tribe would not do "financial" transactions involving numbers greater than two.

  • For example, they would not trade two cows for four pigs.

  • Instead, they would trade one cow for two pigs

  • and then in a second transaction trade another cow for another two pigs.

  • If you had never heard of numbers and you wanted to describe to someone

  • exactly how many gazelles you had seen just over the hill

  • you might use your fingers to represent how many gazelles there were.

  • Of course this would become difficult if there were more than ten gazelles.

  • You could cut marks on a stick

  • or maybe gather a group of pebbles to represent the number of gazelles

  • but then, this would also become cumbersome if there were a lot of gazelles.

  • Another option would be to invent different names and symbols for each possible quantity.

  • This seems like a simple solution but there is still a problem.

  • Remember that you know nothing about our modern base-10 number system

  • which uses only ten symbols in different combinations

  • so you will have to invent a new word and symbol for every possible quantity.

  • For instance, in my primitive tribe on Cocoloco island

  • here are the first thirty numbers we use.

  • zoop

  • floop

  • dop

  • trom

  • mim

  • zap

  • weeny

  • glumby

  • bimpy

  • neechy

  • frump

  • wackit

  • trimble

  • walaki

  • kravitz

  • jolo

  • ponzo

  • kolob

  • krub

  • wallop

  • zoomy

  • mombozo

  • balleemi

  • toramoo

  • fallazit

  • smip

  • bazooloo

  • eekeena

  • eechiwa

  • and ZORTAN.

  • After Zortan we just say "a whole bunch".

  • There were several problems with this number system.

  • First of all, since we had over thirty symbols to memorize, math was really difficult.

  • For instance, if you havewalakicoconuts

  • and then you eatmimcoconuts

  • how many are left?

  • The answer is obviouslybimpycoconuts

  • but it takes many years of school to memorize all the combinations.

  • Also, what happens if you havebazooloococonuts

  • and then someone gives youtrommore?

  • Well, then you'd have “a whole bunch ofcoconuts.

  • In the past, some of the mathematicians on Cocoloco Island

  • actually invented an "advanced" number system

  • with several thousand names and symbols to handle problems like this.

  • But as soon as they did

  • someone always came up with a problem which they did not have a number for

  • by addingzoopto the biggest number.

  • Then one especially brilliant Cocoloconian mathematician

  • came up with the idea of combining symbols.

  • After zortan, the next number would be zortan-zoop

  • then zortan-floop, and so on.

  • When you got to zortan-zortan

  • you then would go to zortan-zortan-zoop

  • and zortan-zortan-floop.

  • This worked well but numbers could get quite long.

  • For instance, our number "one-thousand" in Cocoloconian would be

  • zortan-zortan-zortan

  • zortan-zortan-zortan-zortan-zortan-zortan

  • zortan-zortan-zortan-zortan-zortan

  • zortan-zortan-zortan-zortan-zortan-zortan

  • zortan-zortan-zortan-zortan-zortan

  • zortan-zortan-zortan

  • zortan-zortan-zortan-zortan

  • neechy

  • which we would write as ...

  • After many years people realized that it wasn't necessary to write zortan over and over.

  • The first symbol could just represent the number of zortans.

  • For instance, the number zortan-zortan-zortan-zoop would be dop-zoop

  • three zortans plus a zoop.

  • Zortan-zortan-zortan-zortzan-zoop would be trom-zoop

  • four zortans plus a zoop.

  • The first symbol could represent up to zortan zortans, or 900.

  • This two-symbol system still couldn't quite get up to 1000

  • but nobody had that many coconuts anyway.

  • Then one day a boat arrived from the distant island of Bongopongo.

  • We were all amazed.

  • The Bongoponganians had invented a much better system

  • which could represent really big numbers with much fewer symbols.

  • Apparently, in early pre-history of Bongopongo they must have counted on their fingers

  • because they only used ten different symbols

  • one

  • two

  • three

  • four

  • five

  • six

  • seven

  • eight

  • nine

  • and zero

  • which they calledfingersordigits”.

  • They counted up to bimpy, which they callednine”, using a single digit.

  • Afternine”, they used two digits.

  • The first digit represented some number of tens

  • and the second digit would add from nothing to nine to that.

  • For instance, the number 32 would represent three tens and two ones.

  • The number 47 would be four tens and seven ones.

  • Likewise, the number 80 would be eight tens and zero ones.

  • But here is where their number system was really amazing.

  • After getting up to 99, you would think that they would have to stop.

  • But no!

  • They would just tack on another symbol in front

  • which would now be used to represent hundreds.

  • This could take you all the way to 999

  • which meant nine hundreds

  • plus nine tens

  • plus nine ones.

  • Every time they got to the biggest number they could represent

  • they would just tack on another digit which represented the next bigger number

  • and kept going!

  • This system had some big advantages.

  • First of all there were only ten different symbols to remember.

  • Secondly, every time they added a digit

  • they could represent a number ten times bigger.

  • So with six digits they could represent almost a million.

  • That's a lot of coconuts!

  • Looking back, it is easy to see the problem with the first Cocoloconian number system.

  • Each quantity required a new symbol

  • so when you ran out of symbols, you ran out of numbers.

  • With thirty symbols, the largest quantity that could be represented was thirty.

  • The second system allowed these symbols to be combined in a single number

  • and their values added.

  • But since each symbol could add no more than thirty to a number

  • numbers got big really quick.

  • The third Cocoloconian system could combine two symbols

  • one of which was multiplied by a factor of thirty.

  • This allowed larger quantities to be created with only two digits.

  • However, the largest number was still less than 1000.

  • On the other hand, the Bongoponganian system used only ten symbols.

  • However, with just these ten symbols

  • very large quantities could be represented with just a few digits

  • since each additional digit in a number

  • represented a quantity ten times bigger than the previous digit.

  • This system was simple and efficient

  • and the quantities that could be represented were unlimited.

  • That is why this is the number system that the world uses today.

Hello. I'm Professor Von Schmohawk and welcome to Why U.

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A2 初級 美國腔

代數學前1--數字的曙光 (Pre-Algebra 1 - The Dawn of Numbers)

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    Chun Sang Suen 發佈於 2021 年 01 月 14 日
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