Can you predict recursion easier?

Question

I was just wondering whether there is an easier way to work out what recursion (self-referencing in functions) is going to output.
The reason for me asking this is because I found predicting it really tricky in Area 6 Lesson 6.
Or is the only way to write it out step by step?

Answer 1

1. Look at the else condition: What is the first result?
2. Look at the exit condition: What does it return?
3. Look at the else condition again: What are the intermediary steps?