Hi,
In the first problem try do put PV = 0, because the TVM formula on the calculator assumes that are 5 variables for TVM problems, and in that specific case you�re not interested in PV, right?
In te other one try FV = 0, because that doesn�t interest you...
I know there�s a way to configure the calculator in a way that the formulas for TVM assume by default that the "free variable" (ie the one you�re not using) is always 0, and so you don�t need the procedure I described above.
Hope it helps.....