If 'S' is the amount available after 'n' interest periods for an initial principal 'P' with the discrete compound interest rate 'i', the present worth is given by
(1 + i)n/S
S/(1 + i)n
S/(1 + in)
S/(1 + n)i
(1 + i)n/S
S/(1 + i)n
S/(1 + in)
S/(1 + n)i