°f to °C
One degree Fahrenheit is 0.555555555556 °C, and this shows the working rather than just the answer. Nothing you type here leaves your browser — it is worked out on your own device, so there is nothing to send and nothing to log.
The factor
This one is not a multiplication. °f and °C are both scales with an offset, so converting between them is a stretch and a shift: multiply by 0.555555555556, then add -17.777777777778. A table of pure factors gets this wrong by a constant and is right only at one temperature.
Where these two sit
°f and °C both measure temperature, which is why they can be converted at all. A conversion between families — a length into a weight — is not a conversion, it is a question with a missing quantity in it.