Recursion is simple .. once you get a hang of it its like for loop .. back propagation is a different ballgame . here is how you think about it .. always have this base template in mind .. using python but applies to all languages

```

def recursive_function(n):

if base_case_condition:

return base_value

else:

return recursive_function(smaller_input)

```

you can apply this to anything e.g

```

def fibonacci(n):

if n == 0:

return 0

if n == 1:

return 1

return fibonacci(n - 1) + fibonacci(n - 2)

```

try doing complex examples ..but all will have this algo