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Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and a supportive community. Start your free trial today. # Sum of array

The second task is never covered in videos. I am lost.

I don't even know where to start.

while.swift
```let numbers = [2,8,1,16,4,3,9]
var sum = 0
var counter = 0

while counter < numbers.count {
counter++
}
``` Hi Aaron,

Getting the sum total of the array is very straight forward, the expectation is however that you would have learned this from previous Swift courses which explain basic operators such as sum.

In the case of task 2 of this challenge, we need to use the addition `+` operator or the shorthand `+=` operator. Both of these operators allows us to add a new value to an existing value.

#### Using the basic addition operator `+`

```let number = 1
number = number + 1
```

#### Using the shorthand addition operator `+=`

```let number = 1
number += 1
```

In the case of this challenge, we need to get the total of all the numbers in the `numbers` array. As we have a `counter` variable which we're incrementing the total of; we can use it to access each index within our array and then add the value to our `sum` variable.

```while counter < numbers.count {
sum = sum + numbers[counter]
counter++
}
```

Alternatively, we can also use the shorthand operator for addition which yields the same result as above.

```while counter < numbers.count {
sum += numbers[counter]
counter++
}
```

Hope that helps!