Fahrenheit to Celsius Converter

The trick:

1. Remember that 50F is 10C
2. For every 10F degrees, up or down, add or subtract 5C
3. For a little more accuracy, for each 10F, add/subtract a little extra 0.5C for each 10
4. Feeling heady? More accurate, for each 10F, add/subtract another 5/100ths.

Example: It's warm out, 80F, which is 3 sets of 10 above 50F

1. 50F is 10C, so add 3 sets of 5C -- that's 25C
2. More accurate, add 3 sets of 1/2 degrees (that's 5/10ths) - that's 26.5
3. Better head for math, add/subtract another 5/100ths, for every 10F -- that's 15/100s, 26.65

The trick, here, so much easier....

1. Remember that 10C is 50F
2. For every 5 Celsius, up or down, add or subtract exactly 9F