12-1

It seems like you might be indicating a mathematical operation, subtraction, where you would subtract 1 from 12. If so, the result is:

12 - 1 = 11

If that's not what you intended and you are referring to something else with "12-1," please provide additional context so I can assist you more effectively. For example, if "12-1" is related to a topic you need help with for your university exams, let me know the subject or the type of problem you're trying to solve.