From 96 to 97 I studied in the 9th grade. Since we were forbidden to use the calculators, we were looking for opportunities to pinpoint the system. I found a logarithmic line at home. I asked my father what this was. He told me the calculator and taught me how to use it. I counted on him for six months, and nobody paid attention, until I was once burned by a soundtrack (educational engineer, vocational teacher) and told teachers of the hidden capabilities of this gadget. Well, of course, I had a line to take to classes. My wife is a math teacher. He says that if a single student had learned to use a logarithmic line now, neither she nor any of the pupils would have been able to take it away, but they would also have put up a lot of scores.