User:Robertolyra

Roberto de Menezes Lyra (born April 17, 1959 in Recife, Brazil) Minha página pessoal na Wikipédia em português.[1]

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All Arabic numbers we use today are ideograms created by Abu Ja'far Muhammad ibn Musa al-Khwarizmi (c.778 - c.850).

Al-Khwarizmi was born in Central Asia, where today is placed the Uzbekistan, and then he moved to Baghdad, where he worked as a mathematician during the first golden age of Islamic Science, at the "House of Wisdom".

Using the abacus notations, he developed the manuscript decimal system.

Based on additive angles, he defined the numbers 1, 2, 3 and 4.[2]

And using his knowledge about the abacus manuscript notations, he defined the numbers 5, 6, 7, 8, 9, o.[3]

Roots of the Al-Khwārizmī numerals 1(one), 2(two), 3(three) and 4(four)

Each numeral we use today should be read as a numeric ideogram and the numerals were defined using simple arithmetic.

For example: The numeral 1 (one), 2 (two), 3 (three) and 4 (four), were based on traces with additives angles.

The numeral one has one angle.
The numeral two has two angles.
The numeral three has three angles.
The numeral four has four angles.

Therefore, the symbols for 1; 2; 3; and 4 represent those numbers by having the corresponding amount of angles.

The numeral four gets changed and closed due to the cursive handwriting.

The small abacus of Al-Khwārizmī

This is the small abacus of Al-Khwārizmī abacus with base-five/ten.

All down beads have the five values, and all upper beads have the ten values.

Hypothetically, this kind of abacus was used on the paleography of modern numerals:

five, six, seven (down beads) and
eight, nine, ten (upper beads).

It is assumed to have originated because humans have ten fingers.

Explaining the ideograms of the numerals: 5 (five), 6 (six), 7 (seven), 8 (eight), 9 (nine), and o (ten).

To explain the ideograms of the numerals:

5 (five),
6 (six),
7 (seven),
8 (eight),
9 (nine), and
o (ten),

we need knowledge about the especial small abacus of Al-Khwārizmī that had a base-five/ten like the human hands.

Explaining the figure of base-five/ten small abacus' and the roots of the numerals 5 and 10

The circle is the symbol of a closed hand which has five fingers.

The bead representing the numeral five was placed under the small abacus’ beam.

The numeral ten (the 2nd hand) was placed up on the right of the small abacus’ beam.

Hypothetically, the bead on the top of the beam acquires double value (the ten value).

The small abacus' figure and the cursive circles

The embryo circles: five, six and seven were placed below the abacus’ beam.

The embryo circles: ten, nine and eight were placed above the abacus’ beam.

The abacus’ beam and the down circles with additive up traces

To the circle five, one trace up was added, with one additive angle making the numeral six.

To the circle five were added two up traces, with two additive angles making the numeral seven.

The abacus’ beam and the up circles with diminutive down traces

To the circle ten was added one down trace, with one diminutive angle making the numeral nine.

To the circle ten were added two down traces, with two diminutives angles making the numeral eight.

Drawing the numerals with cursive handwriting

The cursive handwriting makes changes on the format and aesthetic of the numeral five numeral seven and numeral eight.

Drawing the cursive numeral five

The cursive five is still using the abacus’ beam on its structures. Next the cursive numeral five was opened to give real differences to the numeral six.

Drawing the cursive numeral seven

The cursive seven is still using the abacus’ beam on its structures too.

The numeral seven was placed totally under the abacus’ beam, and was the most simplified during its cursive evolution.

The involution of the numeral seven still needs more graphical research, maybe it was necessary due to the similarities that the cursive seven has with the numeral six, or some other Arabic graphical symbol.

Drawing the cursive numeral eight

The continuous cursive handwriting makes changes closing the numeral eight down legs.

Middle Ages

The oldest dated European manuscript containing Arabic numbers is the Codex Vigilanus written in Spain in the year of 976. [4]

By the end of the 12th century (Middle Ages), there were two lines of thoughts among mathematicians:

The algorists, followers of al-Khowarizmi, and
The abacists, who used the abacus as a means of dealing with the unwieldy Roman notation.

In 1202, Leonard of Pisa (also know as Leonardo Fibonacci c.1170 - c.1250) published his Liber Abaci, a book of arithmetic and algebraic information.

During the 14th century, Arabic numerals became widely used by merchants in Italy.

Al-Khwarizmi (Muḥammad ibn Mūsā al-Khwārizmī)

His name is also the origin of the Spanish word guarismo and of the Portuguese word algarismo, both meaning digit.

The words algorism and algorithm stem from Algoritmi, the Latinization of his name.