UNIX: Permissions in UNIX

Question: Permissions in Unix
Answers: with 'chmod' command, the permissions in UNIX can be changed.

Say if someone says to a UNIX admin , 'Grant 740 or 755 permission on this server'
What does 740 or 755 mean?

Read (R) means : 4
Write (W) means : 2
Execute (X) means : 1

754 permission means:
7=4+2+1 ( give RWX permission to users)
5=4+1 ( give read and execute permission to group )
4=4+0+0 ( give read permission to others )