They have different zero points and the temperature increments also vary quite differently. 100 degrees separate freezing and boiling on the Celsius scale, but for Fahrenheit the difference is 180 ...

Say you need to convert 40 degrees Celsius to Fahrenheit. Here’s the order of math you need to perform: (40 × 1.8) + 32, which translates to 72 + 32 = 104 degrees Fahrenheit.