This might have been in Windows Vista as well (I went from Windows XP to 7): Bill's made some improvements on Window's built-in calculator. Still no RPN (Reverse Polish Notation), but it does display the string of numbers and operations as you enter them. Various modes: basic, scientific, etcetera are available. As well: "work sheets" (at bottom of view pulldown), a couple of which are Fuel Economy, one for mpg, and another liters per 100 km. Here's an example: Not included, but handy, would be a function to convert between the two systems. Anyway, to do that: Divide 235.2 by either value.
There is a metric chitload of free and nearly free Windows calculators available for download. I'm 99% sure I have seen them with RPN
Ditto. As for conversion, I use Google as my calculator. Try Googling for these, for example: 7 liters per 100 km in miles per us gallon 50 miles per us gallon in liters per 100 km 74 miles per uk gallon in miles per us gallon 50 miles per gallon in teaspoons per mile 10000 furlongs per fortnight in mph 20000 leagues in feet
Microsoft have their own conversion calculator (Calculator Plus). I've been using it since I started with Win7.
