Fahrenheit to Celsius conversion is given by which expression?

• A. (F-32)/1.8
• B. F/1.8 - 32
• C. (F+32)/1.8
• D. F-32

Answer: (A)

Converting Fahrenheit to Celsius involves two steps: remove the 32-degree offset that defines freezing, then account for the fact that a Celsius degree is larger or smaller than a Fahrenheit degree by the factor 5/9 (10). In practice, you subtract 32 first and then scale by 5/9. This gives C = (F − 32) × 5/9, which is the same as C = (F − 32)/1.8. That’s the expression that correctly converts the units.

If you divide by 1.8 after subtracting 32, you get the same result as the correct form, but options that add 32 instead of subtracting, or that perform the division before subtracting, misplace the zero point or skip the necessary scaling, so they don’t produce the right Celsius value.