As a retired teacher, I am actually surprised at how FEW letters like this were sent to me. Nonetheless, ignorance abounds. I was once in a major chain store where my eye was drawn to a sign advertising chocolate bars for .25 (cents sign). I asked the manager if it were correct. When he assured me it was, I demanded he sell me the bars for 1/4 cent each. The next day, I posted a copy of the sign in my remedial math class without comment. Everyone saw what was funny.