how to calculate time elapsed in 2 datetimes?

A B
27/09/2013 08:03
27/09/2013 11:50
27/09/2013 12:22
27/09/2013 15:25
27/09/2013 15:50
27/09/2013 17:25
30/09/2013 08:10
30/09/2013 14:06
30/09/2013 16:02
30/09/2013 18:36
01/10/2013 07:53
01/10/2013 13:48
02/10/2013 08:00
02/10/2013 13:58
02/10/2013 15:59
02/10/2013 18:32
03/10/2013 15:37
03/10/2013 19:04

How to calculate in cell B the time elapsed in each datetime. sample of formmula: B2=A1-A2

Thanks

Your subtraction needs to go in the other direction. A more current date is a higher value than an older date.

B2=text(A2-A1,"[h]:mm")

27/09/2013 08:03
27/09/2013 11:50 3:46
27/09/2013 12:22
27/09/2013 15:25 3:02
27/09/2013 15:50
27/09/2013 17:25 1:34
30/09/2013 08:10
30/09/2013 14:06 5:55
30/09/2013 16:02
30/09/2013 18:36 2:34
01/10/2013 07:53
01/10/2013 13:48 5:55
02/10/2013 08:00
02/10/2013 13:58 5:58
02/10/2013 15:59
02/10/2013 18:32 2:32
03/10/2013 15:37
03/10/2013 19:04 3:26


I need sum hours and minutes? the result is: 29 hours +342 minutes (342/60=5.7= 5 hours+42 minutes[.7*60=42]) then the result is: (29+5)=34 and 42 minutes.


but wich formula use for automate this?

thanks