Label Cards showing results of a math function


I am attemping to get a label card to show the result of a mathematical formula, a very simple one.

I keep an offset variable that sets a thermostat at a regular offset from my house thermostat. so if I set my house to 70 degrees, (and the room offset is 2 degrees) the room thermostat will be 68 degrees. I have a script that takes care of all that and turns the heat on at that, then off when it reaches 3 degrees above that point.

I want a card to show me this setting, rather than the house setting or the offset. these are the label expressions that I have tried so far:

=items.Housetempset.state - items.BackBedroomTemperatureOffset.state


=Math.subtract(items.Housetempset.state, items.BackBedroomTemperatureOffset.state)

I am missing something and so far have not found an example to help me understand what I need. neither of these expressions work, and only give me a - in the label card.

Any help or ideas would be appreciated.

Thank you,

See this recent discussion:

That was it. This is the answer:

=Number.parseInt(items.Housetempset.state) - Number.parseInt(items.BackBedroomTemperatureOffset.state)