UK calling here. My Fiat doesn't have mph on the speedo as it was replaced (like most things ln the car it broke). I've been doing conversions for years from m

UK calling here. My Fiat doesn't have mph on the speedo as it was replaced (like most things ln the car it broke). I've been doing conversions for years from miles to km, gallons to litres etc. It's annoying but kmh is easy. I want to drive 200 miles. How much will it cost at 44.9mpg and 135.9ppl? 200 / 44.9 x 4.456 x 1.359 - yep random unit conversion in the middle. Beer is metric as well until they sell it to you. Whilst I understand all the problems I can only assume its an issue with education as doing decimal math is no more difficult than any other. Sometimes its easier especially when comparing or scaling magnitudes.