“+”:加号是十五世纪德国数学家魏德美创造的.在横线上加上一竖,表示增加.“-”:减号也是德国魏德美创造的.从加号中减去一竖,表示减少.“×”:乘号是十八世纪美国数学家欧德莱最先使用的.它的意思是表示增加的另一种方法,因而把加号斜过来写.“÷”:除号是十八世纪瑞士人哈纳创造的.它的含义是分解的意思,因此用一条横线把两个圆点分开. “+ ”: The plus sign was created by the German mathematician Wei Demei in the fifteenth century, with the addition of a vertical bar to indicate an increase. “- ”: The minus sign was also created by Weidmüber in Germany. To erect, to reduce. “× ”: The multiplication sign was first used by the American mathematician Oddre in the eighteenth century, and its meaning was another way of expressing an increase, and therefore the plus sign was written obliquely. “÷ ”: The division sign was created by Hana in the 18th century by the Swiss, and its meaning is the meaning of decomposition, so separate the two dots by a single horizontal line.