Uno – the “unit” for dimensionless quantities
I&#x27;ve often felt it to be helpful to treat dimensionless quantities as a smell that the dimensions might be too unspecific. 12 meters &#x2F; 3 meters is just a unitless 4, but 12 meters east &#x2F; 3 meters north is a much more interesting 4 units-east-per-unit-north. Keeping track of these invariant &quot;hidden units&quot; was sometimes helpful to me in physics classes, especially in later classes where nondimensionalizing your equations was so handy.