0400 Allows the owner to read
0200 Allows the owner to write
0100 Allows the owner to execute files and search in the directory
0040 Allows group members to read
0020 Allows group members to write
0010 Allows group members to execute files and search in the directory
0004 Allows everyone or the world to read
0002 Allows everyone or the world to write
0001 Allows everyone or the world to execute files and search in the directory
1000 Sets the sticky bit
2000 Sets the setgid bit
4000 Sets the setuid bit

4 = r (Read)
2 = w (Write)
1 = x (eXecute)

To represent rwx triplet use 4+2+1=7
To represent rw- triplet use 4+2+0=6
To represent r– triplet use 4+0+0=4
To represent r-x triplet use 4+0+1=5

0 – Use set setuid, setgid, or sticky bit
7 – Full permission for owner (rwx = 4+2+1=7)
0 – Remove group permission (— = 0+0+0=0)
0 – Remove world permission (— = 0+0+0=0)