Originally Posted by Turbonium
Km to M is easy to do in the head, but F to C is more difficult.
(F-32)/9*5=C
C/5*9+32=F
What's so hard about that?
Right now it's 69°F. 69-32=37, 37/9=4.1ish, 4.1*5=20.5°C. All done in my head, w/o a calculator or conversion software.
I think where people have problems is they are taught (F-32) * 5/9 =C and C * 9/5 + 32=F, where 5/9 and 9/5 are fractions. Do your division first, then mulitiplication, and it's easier.