UNDER ADDITION

HISTORY OF PLUS SIGN

Our familiar +  sign was not used until only four to five hundred years ago. Diophantus of Alexandria and the Hindus (seventh century A.D.) indicated addition by simply placing all the quantities to be added side by side. 

Diophantus used the symbol, , followed by all the negative terms, side by side, to indicate subtraction. The Hindus indicated subtraction by placing a dot over the quantity to be subtracted (the subtrahend).

In the late fifteenth and early sixteenth centuries, some of the Italian mathematicians introduced symbols into their algebra. Luca Pacioli used a p (from piu, "more") for plus, in his Summa de arithmetica of 1494.

The + symbol first appeared in print in Leipzig in 1489 in an arithmetic by Johann Widman. Here the symbol was used to indicate excess , not the addition operation of today. In 1514 the Dutch mathematician Vander Hoecke used the + symbol for algebraic operation, but it is believed this was used this way even earlier.

It is thought that the plus sign is a contraction of the Latin word et, which was often used to indicate addition.