“+”号是十五世纪德国数学家魏德美创造的。在横线上加一竖,表示增加。“-”号也是魏德美创造的。从加号中减去一竖,表示减少。“×”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。“÷”号是十八世纪瑞士人哈纳创造的。它的含义是分解的意思,用一条横 The + sign was created by German mathematician Wei Demei in the fifteenth century. Add a vertical line, said the increase. “-” is also created by Wei Germany and the United States. Subtract vertical from the plus sign, indicating a decrease. The “x” sign was first used by the American mathematician Oddley in the 18th century. It means another way of saying an increase, so write the plus sign. The “÷” number was created by Hana in the 18th century. Its meaning is the meaning of decomposition, with a horizontal