summing multi inputs
 

Hello;
I have create a running monthly total from several sheets..
One sheet looks like the following.
I have to sum the expenses for each ...

veh # v parts v labor
P498 -159.67 0
V438 6.3 0
P498 21.65 0
P507 174.77 17.5

please note that p498 has more than one entry..

so my question is.. What is the best method to use (formula / macro)(with an
example please) that would sum these numbers up.
The output will go to another workbook, that is used to track monthly
running totals per veh #.

Thanks in advance for your input..

Sam.