Each of the digits in the number 7452318 is arranged in ascending order from left to right. What will be the sum of the digits which are second from the left and second from the right in the new number thus formed?

If 1 is added to each odd digit and 2 is subtracted from each even digit in the number 7531468, how many digits will appear more than once in the new number thus formed?

If 1 is added to each odd digit and 2 is subtracted from each even digit in the number 5431786, what will be the difference between the highest and lowest digits in the new number thus formed?