public static char[] add(char[] arrayOne, char[] arrayTwo, int lengthOne, int lengthTwo)
    {
        char[] sum = new char[20];
        int firstNum, secondNum, smallSum;

        for(int i = 0; i < 20; i++)
        {
            firstNum = (Integer.valueOf(arrayOne[i]) - 48); //48 is the offset of the ASCII value
            secondNum = (Integer.valueOf(arrayTwo[i]) - 48);
            smallSum = firstNum + secondNum;
            if(smallSum >= 10)
            {
                smallSum = smallSum%10;
            }
            sum[i] = Character.forDigit(smallSum, 10);
        }

        return sum;
    }