Hour do i add up the total hours worked

(If i add =b4+c4+d4 I get 00:44)

Monday 04 August 2008 11 August 2008 18 August 2008
in 08:53 07:30 08:53
out 17:11 17:08 17:11
Total hours 07:48 09:08 07:48



Thanks