Keith J. Devlin

“When he was about fourteen years of age, Leonardo would have left the fondaco and most likely traveled with an older merchant,…

— Keith J. Devlin

“a baby’s failure to reach for an object hidden under a blanket does not support the rather dramatic conclusion that the baby…

— Keith J. Devlin

“Having described the basic methods of Hindu-Arabic arithmetic in the first seven chapters, Leonardo devoted most of the remainder of the book…

— Keith J. Devlin

“In chapter 10, he explained how to use similar methods to manage investments and profits of companies and their members, and showed…

— Keith J. Devlin

“By the latter part of the first millennium of the Current Era, the system we use today to write numbers and do…

— Keith J. Devlin

“A significant difference between Pacioli’s book and Treviso Arithmetic is that Pacioli dealt with negative numbers. The concept of negative numbers was…

— Keith J. Devlin

“a mathematician is someone for whom mathematics is a soap opera.”

— Keith J. Devlin

“The choice of ten basic number symbols—that is, the Hindus’ choice of the base 10 for counting and doing arithmetic—is presumably a…

— Keith J. Devlin

“The number system we use today—the Hindu-Arabic system—was developed in India and seems to have been completed by around 700 CE. Indian…

— Keith J. Devlin

“Underlying all this activity—in the customhouses, on the wharves, in every place of business—were numbers. Merchants measured out their wares and negotiated…

— Keith J. Devlin

“European scholars had translated into Latin two important Arabic manuscripts, written by the ninth-century Persian mathematician Abū ‘Abdallāh Muammad ibn Mūsā al-Khwārizmī…

— Keith J. Devlin