floor((0) / 2) - 5 is the ability modifier being applied to your check. Note that an intelligence modifier of 0 is associated with an intelligence score of 10 or 11 (i.e. floor((10) / 2) - 5 = 0). An intelligence score of 0 implies an intelligence modifier of -5 (i.e. floor((0) / 2) - 5 = -5) If you have not accidentally set your intelligence score to 0 on your Character Sheet, this means that you probably have an Attribute (on the Attributes & Abilities Tab of your Character) with a Current value of 0. This 0-valued Attribute represents the ability score that is being applied to your check (it's probably named "intelligence"); look for it on the Attributes & Abilities Tab of your Character. If you find it, delete it, and re-add your intelligence score to your Character Sheet.