> "And in your comment you just called "km" a unit again!" Are you referring to "as the difference in units (km vs miles)"? The base units are meters and miles

> "And in your comment you just called "km" a unit again!" Are you referring to "as the difference in units (km vs miles)"? The base units are meters and miles. I use km there because that is the use (with scale) in the original context. "Unit" can have two different meanings. One is the use of measurement systems: meter vs miles. It can also refer to distinguish between the quantity and the unit in a measurement, such as "1 km" vs "1000 m": in the first case, the "1" is the quantity and "km" is the unit. In the second, "1000" is the quantity and "m" is the unit. As an aside, this sense of unit is often useful in "unit analysis" (also called "dimensional analysis"). https://en.wikipedia.org/wiki/Dimensional_analysis https://en.wikipedia.org/wiki/Dimensional_analysis