I have to determine the future value at the end of the final year's if deposits are made at the beggining of each year into an account paying annual interest of 12%, assuming that no withdrawals are made during the period.

For A is year 1 900, year 2 1,00, and year 3 1,200 , For B is year 1 $30,00, year 2 25,000, year 3 20,000, year 4 10,000, and year 5 5,000, For C is year 1 1,200, year 2 1,200, year 3 1,000, and year 4 1,900. What is my first step and is there an equation for me figuring this out?