I am having problems with my Mathematics of Finance.

The question is find the balance due on the maturity date of the following notes.

Principal Interest Time(days) Partial Payments Balance Due Total Interest Paid

$18,457 12% 120 $5978 on day 34 $3124 on day 55

Here is what I have come up with and the answer is incorrect. This is one of my odd numbers in my book.Could you help me figure out what I am doing wrong, so I can continue on.

$18,457*.12*34/360=$209.18 $5,978-$209.18=$5768.82 $18,457-5768.82=$12,688.18 $12,688.18*.12*55/360=$232.62 $3,124-232.60=$2,891.38 $12,688.18-$2,891.38=$9,796.80 $9,796.80*.12*31/360=$101.23 $9,796.80+$101.23=$9,898.03 $209.18+$232.62+$101.23=$543.03

The answers in the back of the book for the Balance due is $9,862.15 and the Total Interest paid is $507.15.