I need little bit explanation on the below code because I confused and don't understand.

Question

t = 40
def sum(t):
t+= 20
return t
sum(t)
print(t)

Answer 1

I think, you should print sum(t).
After you will understand everything....
print(sum(t))

Answer 2

When you pass t to sum function it doesn't changes the value of original t , rather it creates a new variable named t .

If you are still confused you should search for mutable and immutable data types in python .

t here is a immutable data type.

Answer 3

You have in the function return (t)
Then you call the function with sum(t) but without print. So you dont get a output of the function.
Try it print(sum(t))

Or change the function
Return(t) into print(t)