Learn celsius

Part 1: Here’s an easy way to approximately convert Centigrade to Fahrenheit: “double the Centigrade temp, subtract the first digit of the result from the result and add 32.” Example: 16 C = (32-3)+32 = 61 F. (This tip is from Fodor’s Travel website.) — MF

Part 2: Recomendo reader Don wrote to tell us, “Your Centigrade to Fahrenheit conversion works ‘sorta’ as long as the result of doubling the C number is a two-digit number. I’ve always doubled the C number and subtracted 10%, then added 32. Most folks can figure out 10% and subtract it. Also, this doesn’t result in an approximation, but the correct result.” — MF

Part 3: The US is basically the only country in the world not using metric. It’s not that hard to learn a rough sense of how many kilometers in a mile, or pounds in a kilo. But it is very hard to convert temperatures between Centigrade and Fahrenheit. The solution is to convert all your thermometers to Centigrade: on your phone, in or outside of your house, on websites. Have any digital device display only Celsius, so you can’t cheat. In about a year, you’ll have a reliable and native sense of what’s cool and warm in degrees C. This is supremely handy if you travel anywhere outside of the US. — KK