[°C] = ([°F] − 32) × 5 ⁄ 9
eg 78f -32 = 46 x 5 = 230 / 9 = 25.55c
[°F] = [°C] × 9 ⁄ 5 + 32
eg 25.55c x 9 = 229.95 / 5 = 45.99 + 32 = 77.99f
Easy when you know how 
Fly - that's utter crap, you've only got it to 2 decimal places - I need it to be much more accurate than that!!!

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