How do you convert 50°F to Celsius?

##50^@F = color(green)(10^@C)##

##{: (,"Fahrenheit","Celsius"), ("boiling point",212^@F,100^@C), ("freezing point",32^@F,0^@C), ("difference", 180F^@,100C^@) :}##

So ##color(white)("XXX")180 F^@=100C^@##

##color(white)("XXX")1F^@=100/180C^@##

##50^@F## ##color(white)("XXX")## is ##50^@F-32^@F## ##color(white)("XXXX")=18F^@## above freezing.

##18F^@ = 18xx100/180C^@=10C^@##

##10C^@## above freezing is ##10^@C##