Macnumber where do i find this number

In the apple drop down menu there is a thing that says about this Mac. It will pop up a screen with some basic info, if you click on the part that says version it will show you the serial number. Cut and paste that info into google or go to a mac website that identifies machines by the serial number. Should be easy to find with a google search. Sometimes they give models like 5,1 or 6,2 etc. Sometimes you have to actually look and try before you can get the answer you want.

I have a MacBook late 2009 2.26 unibody. I had to find that out the same way I just described so I could find parts. You can also go to ifixit.com and see if that helps to id your machine.