The plus sign is the calculation symbol used when calculating the addition. Addition and subtraction are the two earliest mathematical operations mastered by human beings, which are recorded in the earliest written records of human beings. Ammers papyrus in ancient Egypt contains symbols of addition and subtraction: two legs "go right" is a plus sign, and two legs "go left" is a minus sign. The latter means "square" in Moscow papyrus. /kloc-Germans in the last twenty years of the 5th century first used the modern plus sign "+"and minus sign "-". "+"and "-"are officially used in the manuscript volume c.80( 1486) kept by Dresden Library in Germany. Weidemann of Czech Republic (1489) used the plus sign "+"and the minus sign "-"in the first printed book.

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