Today's
numbers, also called Hindu-Arabic numbers, are
a combination of just 10 symbols or digits: 1, 2, 3,
4, 5, 6, 7, 8, 9, and 0. These digits were introduced
in Europe within the XII century by Leonardo Pisano (aka Fibonacci),
an Italian mathematician. L. Pisano was educated in North
Africa, where he learned and later carried to Italy the
now popular Hindu-Arabic numerals.
Hindu
numeral system is a pure place-value
system, that is why you need a zero. Only the Hindus,
within the context of Indo-European civilisations, have
consistently used a zero. The Arabs, however, played
an essential part in the dissemination of this numeral
system.
Numerals,
a time travel from India to Europe
The
discovery of zero and the place-value system were inventions
unique to the Indian civilization. As the Brahmi notation of
the first 9 whole numbers...
Before
adopting the Hindu-Arabic numeral system, people used
the Roman figures instead, which actually are
a legacy of the Etruscan period. The Roman numeration
is based on a biquinary (5) system.
To
write numbers the Romans used an additive system: V + I + I = VII (7)
or C + X + X + I (121), and
also a substractive system: IX (I before X =
9), XCIV (X before C = 90 and I before V =
4, 90 + 4 = 94). Latin numerals were used for reckoning
until late XVI century!
Other
original systems of numeration were being used in the past. The "Notae
Elegantissimae" shown below allow to write numbers
from 1 to 9999. They
are useful as a mnemotechnic aid, e.g. the symbol K may
mean 1414 (the
first 4 figures of the square root of 2).
The Ba-Gua (pron.
pah-kwah) trigrams and the Genji-Koh patterns, antique
Chinese and
Japanese symbols, are strangely enough related to mathematics
and electronics. If all the entire lines of the trigrams
(___) are replaced with the digit 1 and the broken
lines (_ _) with the digit 0, each Ba Gua trigram
will represent then a binary number from 0 to 7, and
each number is laid in front of its complementary (0<>7,
1<>6, 2<>5, etc...).
Write "a", "b", "c", "d" and "e" under
the five small red sticks of each Genji-Koh pattern. By
doing so, you will have the 52 manners to CONNECT 5 variables
in boolean algebraics. The binded sticks form a "conjunction" (AND,
.), and the isolated sticks or groups of sticks form
a "disjunction" (OR, +). The pattern at the top left represents:
[("a" and "d") or ("b" and "e") or "c"]
Italy
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