Mathematician:Paolo Dagomari di Prato

Mathematician
Florentine mathematician, astronomer and teacher, best known for being a master of the abacus.

Introduced the idea of using a comma or dot between groups of $3$ digits to separate them into groups for easier comprehension of thousands and millions, and so on.

Nationality
Italian (Florentine)

History

 * Born: 1282 in Prato, Tuscany
 * Died: 1374 in Florence

Publications

 * 1340: Regoluzze

Also known as
Because of his skill with the abacus, usually known as Paolo dell'Abbaco (Paul of the Abacus).

Some sources misspell it as dell'Abaco.

Also known as Paulus Geometrus (that is, Paolo il Geometra, Paul the Geometer).

Some sources misspell di Prato as da Prato.