Engineers that typically use U.S. customary units can be challenged when converting temperatures from Centigrade to Fahrenheit. Sometimes you just want to get an insight of what the Centigrade temperature would feel like. Its not critical to have a precise conversion that the traditional formula F = 9/5C + 32 gives. For nontechnical work there is a quick way of getting an estimate of the Fahrenheit equivalent. Rather than whipping out the calculator on screen, or the telephone or if you are really old fashioned a hand calculator how about exercising that brain and trying this trick.
- Take the temperature in Centigrade multiply by 2
- Subtract 2 times the value of the first digit of the temperature in Centigrade from 1.
- Add 32
Found this trick at