Fifteenth century German mathematician who at a very young age published a book on commercial arithmetic titled Behende und hüpsche Rechenung auff allen Kauffmansschafft. This work is said to be the first printed book in which the now familiar symbols of addition, "+", and subtraction, "-" first appeared, although they were used to indicate surpluses and deficits in warehouse quantities.* Johann Widman (1462-1498) * Source: Jean-Paul Colette, Histoire des mathématiques, tome 1, Éditions du renouveau pédagogique inc., 1973, p. 164