Dans' Mathematica

Arithmetic Mean   In mathematics and statistics, the arithmetic mean (/ˌærɪθˈmɛtɪk ˈmiːn/), or simply the mean or average when the context is clear, is the sum of a collection of numbers divided by the number of numbers in the collection ‎ Definition · ‎ Motivating properties · ‎ Contrast with median · ‎ Generalizations   Arithmetic Sequence   In mathematics, an arithmetic progression (AP) or arithmetic sequence is a sequence of numbers such that the difference between the consecutive terms is constant. For instance, the sequence 5, 7, 9, 11, 13, 15 … is an arithmetic progression with common difference of 2   Arithmetic Series   noun noun: arithmetic series ; plural noun: arithmetic series a sequence of numbers in which each differs from the preceding by a constant quantity (e.g., 3, 6, 9, 12, etc.; 9, 7, 5, 3, etc.). the relationship between numbers in an arithmetic progression. "the numbers a...

For example:   Pierre de Fermat was the most brilliant mathematician of his era and, along with Descartes, one of the most influential. Although mathematics was just his hobby (Fermat was a government lawyer), Fermat practically founded Number Theory, and also played key roles in the discoveries of Analytic Geometry and Calculus. Lagrange considered Fermat, rather than Newton or Leibniz, to be the inventor of calculus. Fermat was first to study certain interesting curves, e.g. the "Witch of Agnesi". He was also an excellent geometer (e.g. discovering a triangle's Fermat point), and (in collaboration with Blaise Pascal) discovered probability theory. Fellow geniuses are the best judges of genius, and Blaise Pascal had this to say of Fermat: "For my part, I confess that [Fermat's researches about numbers] are far beyond me, and I am competent only to admire them." E.T. Bell wrote "it can be argued that Fermat was at least Newton's equal as a pure m...