Plus Minus

I was working in the clerical office of the department, reading and signing some documents, when one of our professors walked in . "Type this document" he told the typist. She took it. "How do I type plus-minus?" she asked. It was to give a range, e.g. 23 plus or minus 3, meaning 20 to 26. "Um ... your computer keyboard does not have that minus below the plus sign key?" he asked. "No" she said. Actually no keyboard has that sort of key. But I did not educate him. Usually he seemed to know everything, and would not welcome new suggestions. "In that case type as plys followed by a forward slash and then minus" he said. She seemed to be happy with that. he went away. "Do you have a word file open?" I asked her. "Yes" she said. "Go to the end and press enter" I said. She did so and looked at me for the next instruction. "Now type +" I said. After she had done that, I said "Now select the + with your mouse and press Ctrl and U keys together." She did that. "Now click somewhere else and look at what you have got" I said. She did that and looked at me with new happiness. She had the minus sign below the plus sign typed. "There you are!" I said. "quite easy!"