Leonardo da vinci , 1452–1519, was an Italian painter, sculptor, architect, musician, engineer, and scientist, b. near Vinci, a hill village in Tuscany. The  creative power of Leonardo mark him as a supreme example of a genius. He depicted in his drawings, with scientific precision and consummate artistry, subjects ranging from flying machines to caricatures; he also executed intricate anatomical studies of people, animals, and plants. The richness and originality of intellect expressed in his notebooks reveal one of the greatest minds of all time.

Leonardo invented some of his own mathematical symbols and terms. Many scientists of his time did this because number notation was not standardized until after the invention of the printing press. This made it difficult for scientists and mathematicians to communicate their ideas to each other. The symbols used for the numbers one through ten come down from ancient India, Greece, Rome, and in medieval Spain.

Leonardo also used "mirror writing" going from right to left on the pages of his notebooks. He was left-handed so maybe this was a matter of convenience. He started every page on the left hand page of the book, or back side and worked over onto the front. Paper was expensive and scarce so Leonardo scribbled on every scrap he could find. These scraps were then assembled. Schools have complained that Leonardo's notebook are a terrible scribble of drawings and writings on myriad subjects like a continuous stream of consciousness. Two thirds of his notebooks have never been found.

Leonardo studied math on his own after he finished his learning as a painter. He had trouble with math and calculating square roots. He doubted that some of the rules of arithmetic were even true.He turned to rely on manners for solving geometry problems.

"In 1483, when Leonardo is 31 years old, he is hired by the Duke of Milan as a military engineer. Milan was the center of arms process in Italy at this time. Why did he change his career? Maybe he like machines.     

It paid well because in 1502, he changed jobs and went to work for nothing other then Cesare Borgia. His job description is chief designer and an engineer. Leonardo spends his last years working for the French Govenor, Charles d'Amboise, and King Francis I. The King gave him a pay for his retirement, and he dies in 1519 at Cloux near Amboise."