The plus sign "+"and the minus sign "-"in the four operation symbols were created by German mathematician Weidemann. The multiplication symbol "×" was first used by the British mathematician Audrey in the17th century. The division symbol \u was created by Ryan of Switzerland in the17th century. The abbreviations "sin", "TG" and "ses" of trigonometric functions were first put forward by Gillard in 1626, and Swiss mathematics should be changed in 1748. The equal sign "=" was first created by Robert Rae Koda, a British royal court doctor in the 6th century. Multiplication symbols and comparison symbols were formally used in Leibniz, Germany, a famous mathematician and founder of calculus in17th century. Parentheses [] first appeared in Varis's works in17th century, and braces {} were created by David, one of the founders of16th century algebra, and were used for mathematical calculation. Greater than sign ">" and less than sign "