Fahrenheit - °F

Fahrenheit (°F) is a unit of measurement for temperature in the English system. Equal to
                                  1.8 °C + 32.

The majority of countries use the centigrade scale rather than the Fahrenheit scale. The approximate conversion is typically used:

                             °F = 2 °C+ 30°

Comparing to the exact formula of

                           °F = 9/5 °C +32,

we find the ratio 9/5 is approximated to equal 2, and the temperature of 32° is changed to 30° simply to make easier to work with.

So the temperature of 20°C is commonly accepted as normal room temperature. Using the approximate formula, we determine the equivalent Fahrenheit temperature equal to 70°F.