```python
def add_elements(arr, k):
    """
    Given a non-empty array of integers arr and an integer k, return
    the sum of the elements with at most two digits from the first k elements of arr.

    Example:

        Input: arr = [111,21,3,4000,5,6,7,8,9], k = 4
        Output: 24 # sum of 21 + 3

    Constraints:
        1. 1 <= len(arr) <= 100
        2. 1 <= k <= len(arr)
    """
    total = 0
    for i in range(k):
        num = arr[i]
        # Check if the number has at most two digits
        # For negative numbers, we consider the absolute value for digit count
        if abs(num) < 100:
            total += num
    return total
```