How to follow the effect of a function on a function

Question

I don't understand when you have for example

func(func(arg)

Or func1(fun2(arg))

How to follow the program and what's happening. Where do I need to start reading from? It made me confused.

Answer 1

But how to follow the effects on thr arguments

Answer 2

Idoredid123

Inside function will work first then outside function.

https://code.sololearn.com/cgfonDJu8pH0/?ref=app

Answer 3

Oh. Thanks

Answer 4

Great explanation by the way.