13 years ago your gramps opened an account with an interest of 4% compounded annually. how much 13 years ago?

the whole problem is.......your gramps had started a savings account for yo 13 years ago. the bank informs you that the account has $835.55 in it. if the interest rate was 4%compounded annually, ho much did pops deposit 13 years ago? intelligent detailed drawn out solution will get my vote so aim high.