1. To exercise.
The man spends most weekends working out at the health club.
2. To solve a problem.
I could not work out the math problem on the final examination.
3. To accomplish something, to arrange something.
Recently, we worked out a system for calculating our expenses at work.
4. (for the best) To end successfully, to prove effective or satisfactory.
I hope that everything will work out for my friend when she moves to London next week.