Slide rule was a fantastic extension (or addition) to logarithmic tables.. I was using both during my studies (tables at high school, slide rule (Faber-Castell Darmstadt electro) at uni. The first exam I had on year one (uni) was slide rule calculations).
At some point, I was able to "use" slide rule in my mind (I think I had photographic memory.. not any more, unfortunately), the accuracy was ~10% or better (for up to 2-3 multiplications/divisions).
The most practical slide rule I had was round one (
still can be found on ebay, made in USSR back in late '60-ties.. It could be used with single hand, and conveniently stored in pocket :-)
And yes, I am sure I would know how to use it today, provided I had one
