In his 1489 treatise, Johannes Widmann referred to the symbols − and + as minus and mer (Modern German mehr "more"): "was − ist, das ist minus, und das + ist das mer".
The − may be derived from a tilde written over ⟨m⟩ when used to indicate subtraction or it may come from a shorthand version of the letter ⟨m⟩ itself. The + sign is a simplification of the Latin: et (comparable to the evolution of the ampersand &). The symbols (P with overline, p̄, for più (more), i.e., plus, and M with overline, m̄, for meno (less), i.e., minus) appeared for the first time in Luca Pacioli's mathematics compendium, Summa de arithmetica, geometria, proportioni et proportionalità, first printed and published in Venice in 1494. In early 15th century Europe, the letters "P" and "M" were generally used. Nicole Oresme's manuscripts from the 14th century show what may be one of the earliest uses of + as a sign for plus. The Egyptian hieroglyphic sign for addition, for example, resembled a pair of legs walking in the direction in which the text was written ( Egyptian could be written either from right to left or left to right), with the reverse sign indicating subtraction: Though the signs now seem as familiar as the alphabet or the Hindu-Arabic numerals, they are not of great antiquity.
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