My memory is so bad. It sputters, coughs & wheezes up surprising stuff, appearing
out of a fog, or washed up on the beach like they were messages in a bottle.
It occured to me that my ol' dad told me, probably 40 years ago, an easy formula for
converting between Fahrenheit and Centigrade.
within a minute or two, after I stopped straining my brain.
Here it is: Whatever temp you have, in either Centigrade
or Fahrenheit, add 40 to the number. (I recalled the number 32 at first, incorrectly,
and found that value generated had an error of a few degrees.)
After adding 40, multiply by either 5/9 or 9/5. If you want to convert Fahrenheit
into Centigrade, multiply by 5/9. Then subtract that same 40.
That will be your converted temperature.
[(F + 40) 5/9] - 40 = C is the formula for converting F into C.
[(C + 40) 9/5] - 40 = F is the formula for converting C into F.
For easy remembering, just add 40 and multiply by either 5/9 or 9/5,
then subtract 40.