Use a 'code block' in the 'new' reddit to paste code so we can see indents which are vital to python! for i in range(n + 1): sum = sum + i * i * i when you say 'for i in range(n + 1)' you are creating a variable called 'i' and setting it equal to the first value in the second part of the line called range(). every time the loop loops, i becomes the next value in the second part of the line (in this case range()) Check this code out to understand it: my_list = ['potato', 'pineapple', 'strawberry', 'banana', 'orange'] for var in my_list: #instead of 'i' i used 'var' you can use any name you want, since you are creating the variable. var is = to a value in my_list, and will go to the next value every time the loop loops. This will run a total of 5 times, because there are 5 items in the list we are looping through (my_list) print(var) now put that in your terminal/whatever and see the output, itll look like this: potato pineapple strawberry banana orange its the same with range() -- example: range(5) just means every number between 0 and 5, including 0 but not 5. so range(5) has 5 items, 0, 1, 2, 3 and 4. our loop should run 5 times: for i in range(5): print(i) you should see the output: 0 1 2 3 4 if you ever want to know more about certain parts of python, google it, for example: 'python range()' will give you tons of results that are helpful. Answer from Sadapy on reddit.com