Hi , im having trouble with addition in VB.NET 2003

I have a listbox which the user inputs a variety of numbers, in the form (minutes.seconds) so, (24.32)

I am looking for some code/tips/help that adds the total in the listbox, continually updating the total.

Eg. User Adds 22.32

Total = 22.32

User Adds 21.12

Total = 43.44 e.t.c

Thanks !