If it takes Joann 112 hours to complete each math problem and she has 23/112 of an hour available, we can calculate the number of problems she can complete by dividing the available time by the time it takes to complete each problem.
Number of problems = (Available time) / (Time per problem)
Number of problems = (23/112) / (1/112)
Number of problems = 23
Therefore, JoAnn can complete 23 math problems in 23/112 of an hour.