Wednesday, January 20, 2010

Math-History of numbers

Hi everyone,

From the Math video, I learnt that:

-using a whole lot of symbols is confusing

-most civalisation use symbols, but some use objects

-there are many ways to solve a problem


Below is the information from the Math Powerpoint:


The numbers were represented by letters but not in the dictionary order (known as huruf al jumal which meant "letters for calculating" )

abjad is just the first four numbers (1 = a, 2 = b, j = 3, d = 4).

The numbers from 1 to 9 were represented by letters,

then the numbers 10, 20, 30, ..., 90 by the next nine letters (10 = y, 20 = k, 30 = l, 40 = m, ...),

100, 200, 300, ... , 900 by the next letters (100 = q, 200 = r, 300 = sh, 400 = ta, ...).

There were 28 Arabic letters and so one was left over which was used to represent 1000.

pastedGraphic.pdf

(this is the 1st version)


The numbers changed their form somewhat 100 years later when this copy of one of al-Biruni's astronomical texts was made.

pastedGraphic.pdf

(in 1082..)


Note that 2 and 3 were rotated by 90 degrees, as you will see later


pastedGraphic.pdf

(This is almost the numbers that we use today, except for the numbers 4 and 5)



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