Username checks out ;) That's neat, I've never had one of those but used a linear one for years for quick order-of-magnitude answers. I got to use it just as modern pocket calculators took off, the first ones were only four function jobs and they were priced insanely high so slide rules were more economic for the kind of problems I ran into in highschool. My maths book even had a whole chapter on using them. Then; after a few years I got a Ti-57 and that was that for the sliderule, that thing was programmable.