Adding substance to the above critisizm, in your 'for loop' notice the following:

for i in range(0, 4):

will only check your remaining if, elif, else statements for the index 0 to 3 in arr1, arr2.

for i in range(0, len(arr1)):

will check those statements for the index 0 up to len(arr1) - 1 (this allows the program to scale with a possible change in list size)

We are told the list length will be the same so modifying your program with this new range in your for loop will suffice.

:P

If it was >= then v could take the v = 0 value in the condition and then you would indeed have a division by 0. Without the = sign, the condition goes to the else part and no division by zero is performed.