What does the following permissions mean?:

777 - You give the owner, group and other: Execute (1), Write (2) and Read (4); 4+2+1 = 7. 644 - Owner has Read (4), Write (2), 4+2 = 6; Group and Other have Read (4). 750 - Owner has x+r+w, Group has Read (4) and Execute (1); 4+1 = 5. Other have no permissions.