O(n^2)

function printAllNumbersThenAllPairSums(numbers){
    numbers.forEach(function(number) {
        console.log(number);
    })
    
    console.log('sums:')
    numbers.forEach(function(firstNumber) {
        numbers.forEach(function(secondNumber) {
            console.log(firstNumber + secondNumber);
        })
    })
}

// O(n + n^2)
// O(n^2)

printAllNumbersThenAllPairSums([1,2,3,4,5])