Line 9 on Colorado Form 104 says to subtract line 8 (deductions) from line 7 (adjusted income) to arrive at Colorado taxable income, line 9. It would be $0 if line 8 was more than line 7, as that would make the taxable income negative. If you mean line 7 is more than line 8, then there would appear to be a calculation error and there would be no way to overide line 9.