An important benefit of TDD is defining doneness. In simple algorithmic programming, if you come up with a couple scenarios where correctness is easily asserted, its easy to enumerate them in a unit test and keep coding until they all work.
Sometimes unit testing can be hard for beginners, if there are many dependencies and you start to run into scenarios where mocking objects is necessary.
However, if you can make a simple statement about correctness, and it is easy to type out, then definitely write it down in code.
You may also note that if a simple statement of correctness is not easily described, you may not fully understand your problem.
Good luck...
