$1.$ Write a phyton script that emulates a simple small calculator

$$ Ask the user for $2$ numbers and the operation to perform

$$ The operations needed are addition, subtraction, multiplication, division

$$ How the user is to input these is up to you.

Show the user the result of the operation

$2.$ What$$s Recursion? What$$s the base case?

$3.$ Here is a minimal program with a recursion:

def recurse$()$:

recurse$()$

What happens if you call this function in the console? And Explain

$4.$ Consider the following example:

def countdown$($n$)$:

if n $<=0$:

print $(\text{'}$Blastoff$!)$

else:

print $($n$)$

countdown$($n$-1)$

a$.$ Is this a recursion? explain

b$.$ What$$s the base case in this function?

c$.$ Is this infinite recursion? And why?

d$.$ Step$-$by$-$Step explanation for countdown$(3).$

$5.$ The factorial operation consists of the following equation:

n$!=$n$*($n$-1)*($n$-2)*..\mathrm{.}3*2*1$

It can also be expressed as:

n$!=$n$*($n$-1)!,0!=1$

Write a function that uses recursion to calculate the factorial of a given number n

What is the factorial of $9?$