mm3@Mohad-Badeel:/media/mm3$ ls -la
total 146
drwxrws---+  8 mm3  mm3  4096 May 21 12:37 .
drwxr-xr-x   3 root root 4096 May  5 08:26 ..
drwxrwxrwx  12 mm3  mm3  4096 May 21 12:37 NuAlpha06Tb
drwxrwxrwx+ 11 mm3  mm3  4096 Mar 18 12:58 NuBeta8Tb
drwxrwxrwx  16 mm3  mm3    28 May 10 16:31 Rho1904
drwxr-xr-x  11 mm3  mm3    11 May 11 09:44 Rho4ext
drwxr-xr-x  19 mm3  mm3    20 May 11 10:20 Rho9ext
drwxrwxrwx  11 mm3  mm3    14 May  3 09:51 RhoCube2004


What do the numbers mean?
Why do I have a + symbol on a folder