Need formula dealing with time, hours & minutes

[scarames]

I've got a worksheet that deals with dates and time. Similar to a checkbook, I need to take the balance and subtract what's taken from that. But the writer copied this from another software program and it's in this format. How do I convert it to a time format? Or is that what I really need? Right now the taken and balance are both in a general format. I just need to know on any of the given days what the balance of this person's time was in hours and minutes. Thanks for any assistance you may be able to give. Excel 2007. BTW, I don't really know how to write code.

Date	       Source	                Taken	Balance
1/1/2009	       Balance Fwd		                480h00
1/5/2009	       Timekeeping Usage	1h25	
1/22/2009	       Timekeeping Usage	10h00	
1/23/2009	        Timekeeping Usage	7h00