A helpful overview of chmod permissions.

Permission	User	Group	Other
Read	4	4	4
Write	2	2	2
Execute	1	1	1
	U	G	O
	X	X	X

Numeric	Permission
777	rwxrwxrwx
755	rwxr-xr-x
644	rw-r–r–
700	rwx——
750	rwxr-x—