i do not understand where to syaty, i continue to do compound interest but very confused on how they get the answer

Present value with changing years). When they are first born, Grandma gives each of her grandchildren a $2,500 savings bond that matures in 18 yeurs. For each of the following grandchildren, what is the present value of each savings bonds if the current discount rate is 4%? a. Seth turned sixteen years old today, b. Shawn turned twelve years old today c. Sherry turned eight years old today. d. Shela turned three years old today e. Shane was just bom