In 2015 I took a slide rule with me when I took my US ham radio license exams. I also took an HP-15c [1], which is what I actually used, but I wasn't sure that

In 2015 I took a slide rule with me when I took my US ham radio license exams. I also took an HP-15c [1], which is what I actually used, but I wasn't sure that the calculator would be allowed [2] so brought the slide rule just in case. The exam is multiple choice and usually the choices are far enough apart that you don't need very much accuracy to figure out which one must be the right one, so even rudimentary slide rule skills would be sufficient. You usually just need to get 1 or 2 significant digits and the right order of magnitude. [1] https://en.wikipedia.org/wiki/HP-15C https://en.wikipedia.org/wiki/HP-15C [2] If your calculator has memory or is programmable you have to convince the examiner that you have cleared memory and erased all your programs.