when were the plus and minus signs first recorded
Plus and minus signs In Europe in the early 15th century the letters "P" and "M" were generally used.[3][4] The symbols (P with line p̄ for più, i.e., plus, and M with line m̄ for meno, 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.[5] The + is a simplification of the Latin "et" (comparable to the ampersand &).[6] 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.[7] 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".[8] They weren't used for addition and subtraction here, but to indicate surplus and deficit; their first use in their modern sense appears in a book by Henricus Grammateus in 1518.[9][10]
Quadrant (plane geometry) These are often numbered from 1st to 4th and denoted by Roman numerals: I (where the signs of the (x,y) coordinates are (+,+)), II (−,+), III (−,−), and IV (+,−). When the axes are drawn according to the mathematical custom, the numbering goes counter-clockwise starting from the upper right ("northeast") quadrant.