Mathcad prime 4.0 issue with °F units

There are two types of temperature units in Prime, absolute and relative. You're using the absolute Fahrenheit units. This means that every temperature is converted to absolute temperature in kelvin, then subtracted, then the result is converted back to Fahrenheit because you requested the result to be Fahrenheit.

You should use Delta°F instead of °F for the result. See ttokoro's examples below.

Success!
Luc

---

@AL_9913769 wrote:

I'm subtracting 2 temperatures. But Mathcad gives an unexpected answer:

ΔT should equal 280°F.

 

---

The 350°F are an absolute temp, but the 70°F are a relative temp.

 So IMHO the appropriate approach would be