What is best way of displaying dims and working in inches-decimal when currently mm?

I won’t pretend that I understand this inch and feet stuff but when I enter 1’2.2" as the length of a line and then check the length of that line in model units (being mm), I get 360,86 mm. When I use a unit converter to put that back to feet I get 1,18333 feet. And 0,18333 feet appears to be 2,19996 inches. In other words, I would say that it does work…