I am following the guide to build new character sheets, and am just trying to figure out some real basic stuff. I should be able to define an attribute "attr_str" and an attribute "attr_ref" and then create a new attribute "attr_dex" which is an average of the two. I set up str and ref as follows: <input name="attr_str" value="30" type="number"> <input name="attr_ref" value="30" type="number"> <input name="attr_dex" value="(@{attr_str}+@{attr_ref}/2)" type="number" disabled="true"> Am I just missing something super basic here? Thanks in advance.