Linux file permission

Brief
Surmise about Linux file permission

If you run 'ls -alt', and then the file permission is displayed.
ls -alt
drwxr-xr-x 2 root root 6 Jul 24 14:03 tmp

The status from left means
# File type. d means a direcory.
d

# a file mode of a file owner
rwx

# a file mode of a file group
r-x

# a file mode of another group users
r-x

# the number of link to files
2

# a owner name of a file or a directory
root

# a group name of a file or a directory
root

# used bytes
6

# last updated date
Jul 24 14:03

# a file name or a directory name
tmp

The meanings of r and w and x is like the below.
r: enable to refer
w: enable to change
x: enable to execute

r and w and x are allocated numbers.
r=4
w=2
x=1