# For loop lists - calculating total/sum

Hi this is a simple question asked out of curiosity.

I am wondering why the formula used below does not factor in the exact values in the original list. The total calculated is 45, when it should be 42. I ended up using range(len()) to rectify this. But when checking as to what caused this, I see that print(list[a]) returns a few different numbers.

The output has an additional 4 and 5, but does not have the number 3 as in the original list.

list = [0, 9, 5, 4, 8, 2, 3, 0, 1, 5, 3, 2]

total = 0
for a in list:
total += list[a]
print(list[a])
print(total)

Output =
0
5
2
8
1
5
4
0
9
2
4
5
total = 45

Hello @Astra0508 , welcome to the community!

when you use `for a in list`, the `a` is already the value inside the list, not the index. Because of this, you donâ€™t need to use `list[a]` to access the value.

What youâ€™re trying to do, can be done like this:

``````total = 0
for a in list:
total += a
print(a)
``````

In your `for` loop, the `a` will represent each value in the list in each iteration. As the first value in the list is 0, in the first iteration, `a` is equal to 0. Therefore, when you do `list[a]`, youâ€™re doing `list[0]`, which means youâ€™re accessing the index 0 of the list, which is 0 itself. Thatâ€™s the first output you have.

When the `for` loop moves on to the next iteration, `a` becomes 9 and therefore `list[a]` is equals to `list[9]`, which means youâ€™re accessing the element of index 9 in your list. That element is 5, which is your second output.

An so onâ€¦

Also, itâ€™s not a great practice to name a list as `list` in python, because this is already the name of the function `list()`, used to create lists.