```
numbers = [3,5,7]
def total(numbers):
result = 0
for i in range (0,len(numbers)):
result += numbers[i]
return result
print total (numbers)
```

Both of these work. i wish to know why in the top one the only way i can get it to work is with `result += numbers[i]`

The one on the bottom will only work if i use `result = result + i`

If i use `+=`

on the bottom one it wont run

If i use = numbers + i OR = results + i on the top one it also wont work

WHY?

```
numbers = [3,5,7]
def total(numbers):
result = 0
for i in numbers:
result = result + i
return result
print total (numbers)
```