I'd argue that a sliderule is at least something you can manipulate with your hands and immediately see the output relationship.
Tangent, I use a tape measure at work and you can fold it back on itself to make a basic slide rule for quick addition and subtraction without bothering with fractions :)
Tangent, I use a tape measure at work and you can fold it back on itself to make a basic slide rule for quick addition and subtraction without bothering with fractions :)