### Timeline

#### Leonardo of Pisa

Born in 1170 in pisa, Italy , most known as Fibonacci “Son of Bonacci”.

His father was trader so take leonardo to many places where he studied.

He spread the use of arabic numerals all over Europe. He knew both roman and arabic numerals and thought arabic # were easilier than roman for operations. As he said"These are the nine figures of the Indians: 9, 8, 7, 6, 5, 4, 3, 2, 1. With these nine figures, and with this sign 0 ... any number may be written”.

Wrote the Liber abaci (2nd book to talk about arabic numeral)Known as abacus or calculus book.

He discovered the fibonacci sequences that consist that each succeeding number is the sum of the two previous ones and connected it to Phi the golden number.

#### Nicole Oresme

Born 1320 Germany and Died 11 july 1381

He used a system of rectangular coordinates centuries before his country man Rene Descartes popularized the idea, as well as perhaps the first time-speed-distance graph. He was the first to use fractional exponents, and also worked on infinite series, being the first to prove that the harmonic series 1⁄1 + 1⁄2+ 1⁄3 + 1⁄4 + 1⁄5... is a divergent infinite series

### The History of Negative Numbers

What would be of a geometrical magnitude whose value was less than 0?

The first to use negative quantities were the Indian mathematics who used them for counting necessities

Brahmagupta used the ideas of 'fortunes' and 'debts' for positive and negative.

During the 14th century Fibonacci began to think about them but still didn't consider them as a possible solution for an equation

The negative numbers were called "numberi absurdi" and were denied for a long time before they were consider a possible solution for an equation

If wasn't until the middle of the XVII century that the English mathematician, John Wallis dared to put negative coordinates to the point of a curve.

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Medieval Math. (n.d.). Retrieved March, 2017, from http://quatr.us/medieval/science/medievalmath.htm

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No Title. (n.d.). Retrieved March, 2017, from http://www.math.tamu.edu/~dallen/history/mideval/mideval.html

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Numeri absurdi. (2008, December 03). Retrieved March, 2017, from https://insegno.wordpress.com/2008/12/03/numeri-absurdi/

L. (1970, January 01). Números Negativos. Retrieved March, 2017, from http://alejandralopezrodriguez.blogspot.com.co/2009/11/numeros-negativos.html

Deuda con los números negativos: un poco de historia. (n.d.). Retrieved March, 2017, from http://www.reformamatematica.net/comunidad/espa/node/25

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Created with images by jitze - "Chambered Nautilus Shell - detail"