Originally Posted by
BobL
I wouldn't be too quick to sneer or laugh at fractions, it's not old fashioned or quaint but a real mathematical thing.
Many formulas in Physics and maths use fractions.
For example; the volume of a sphere is not 1.33 ∏ r^3 but 4/3 ∏ r^3 and there is a difference, especially if you have to get to the moon..
The moment of inertia for a spherical shell with the axis through the centre is 2/3MR^2
In practice in the shed I do tend to work with metric systems but as I also often use imperial drill, tap & die sets and also use Vernier callipers with the fractional display I'm often mixing and matching.