Beautiful! ... I used some version of the CTCS-552 from 10th to 12th grade (and still have it around here somewhere). The slide-out card has trig tables and qu

Beautiful! ... I used some version of the CTCS-552 from 10th to 12th grade (and still have it around here somewhere). The slide-out card has trig tables and quite a few formulas. I also have one of my father's slide rules which he used for the first 1/3 of his EE career. There was a huge benefit of using a slide rule - it reinforces your "mental math" since you're keeping track of the magnitude of your calculations in your head. When I later started using a calculator, it was really obvious if I'd mistyped part of a calculation.