According to the output you are getting, this is how your code must be -
start = 5-2009-30
start = str(start)
start = list(start.split("-"))
print(start)
What your code is doing, is that, it subtracts 5, 2009, and 30. Because the values you gave in that variable are integral, and the "-" symbol means subtraction, it divides the numbers. Then It is converting the answer into a string, then converting into a list, and printing the difference. That is why you are getting the wrong output. You can avoid this by, placing the data between the quotating marks. Converting into string means that, it just converts the answer into a string, thats why even when you typed the str() function, it didnt give any result
So your final code should be -
start = "5-2009-30"
start = list(start.split("-"))
print(start)