(Beginner) Why is this not correct?

#Add the input number 4 times. Ex. 3+3+3+3
#If the input is 3, the output will be 12

num = int(input("Num: "))

for x in range(2):
    num += num

print(num)

Using an app called "Easy Coder" and
for some reason, the code above is not correct.

Is there a better way to do this? so the actual process of the code is("3+3+3+3) and not(3+3) + (3+3)

Edit: Sorry, I forgot to mention, that this is an exercise related to
looping.
The task:

Write a program that uses a for loop to calculate any
number X 4.
Hint – Add the number to a variable 4 times.

>Solution :

To add 4 times, use a separate variable for the total and loop 4 times instead of twice

num = int(input("Num: "))
total = 0

for _ in range(4):
    total += num

print(total)