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加、减号“+、-”是15世纪德国数学家魏德曼首创的。他在横线上加一竖表示增加、合并的意思;在加号上去掉一竖表示减少、拿去的意思。
Plus, minus, “+, -” was first invented by German mathematician Weidman in the 15th century. He added a vertical line that increase, the meaning of the merger; remove the plus sign that reduce, take meaning.