I'm 47 and I never really knew what a slide rule was for until a few years ago. When I did I thought "Oh, we've had calculators all my life, now I know why I n

I'm 47 and I never really knew what a slide rule was for until a few years ago. When I did I thought "Oh, we've had calculators all my life, now I know why I never learned about them." They are interesting and I can see how they would have been hugely important 60 years ago.