Decimal

Decimal, or less commonly, denary, usually refers to the base 10 numeral system.

History

Decimal writers

• c. 3500 - 2500 BC Elamites of Iran possibly use early forms of decimal system. http://www.chn.ir/english/eshownews.asp?no=1622 http://www.mpiwg-berlin.mpg.de/Preprints/P183.PDF
• c. 2900 BC Egyptian hieroglyphs show counting in powers of 10 (1 million + 400,000 goats, etc.).
• c. 2600 BC Indus Valley Civilization, earliest known physical use of decimal fractions in ancient weight system: 1/20, 1/10, 1/5, 1/2. See Ancient Indus Valley weights and measures.
• c. 1400 BC Chinese writers show familiarity with the concept: for example, 547 is written 'Five hundred plus four decades plus seven of days' in some manuscripts.
• c. 598–670 Brahmagupta – decimal integers, negative integers, and zero
• c. 790–840 Abu Abdullah Muhammad bin Musa al-Khwarizmi – first to expound on algorism outside India
• c. 920–980 Abu'l Hasan Ahmad ibn Ibrahim Al-Uqlidisi – earliest known direct mathematical treatment of decimal fractions
• 1548/49–1620 Simon Stevin – author of De Thiende ('the tenth')
• 1561–1613 Bartholemaeus Pitiscus– (possibly) decimal point notation
• 1550–1617 John Napier– decimal logarithms