1. Recurse to the last element and return the carry over. Add carry over to the current element and return carry over. If the calling function receives a carryover as 1, then add a new node to the linked list at the start of the list and set it to 1. 2. 3. 50,000,000,000 = 50*10^9 = 50 * 10^3 * 10^3 * 10^3 = 50* 2^30 = 2^5.5 * 2^30 = 2^35.5. Assuming that you know that 1000 is 2^10, and roughly guessing that 50 = 2^5.5, you can answer it as 35.5 years.