The formula for discounting any specific period cash flow in period t is:

1 Cash flow from period t divided by (1+discount rate) raised exponentially to t-1

2 Cash flow from period t divided by the (discount rate) raised exponentially to t

3 Cash flow from period t divided by (1+discount rate) raised exponentially to t

4 Cash flow from period t divided by the (discount rate) raised exponentially to t-1

choose one of the 4 above