why cant I get this update field value condition to work

I am trying to add a value to the number field depending on which radio button is seletected for how large is your home.  But it wont post the value.  

https://form.jotform.com/70379209481158

I cloned your form to test it and the condition should work as you have it:

When I checked in the form, the correct number was updated in the calculation field:

This is with the calculation field shown in the form instead of hidden.

If this is still not working on your end, let us know and we will take another look.