Why do physicists continually use the term "per" when they are multiplying units? Division is the appropriate operation when the term "per" is encountered. For example, Joules per kilogram per Kelvin. Physicists denote this as J/kg*K. Why do so many physics textbooks write "per" when kilograms are being multiplied with Kelvins? There are other examples, such as N*m^2 / kg^2. Here N*m^2 is recited as "newton-meters squared", not "newtons per meter squared". So, shouldn't the units in the initial example also be read as "kilogram-Kelvins"?