Ubuntu command find

Ubuntu command find -- general Linux technology-Linux technology and application information. The following is a detailed description. As a result of my professional needs, I have just been familiar with Linux and I am not very familiar with the usage of some commands.
Problem:
I recently created a Ubuntu instance in the VM;
Version: Linux version 2.6.32-22-generic (buildd @ rothera) (gcc version 4.4.3 (Ubuntu 4.4.3-4ubuntu5 )) # 33-Ubuntu SMP Wed Apr 28 13:27:30 UTC 2010 (obtained through cat/proc/version)
In this version, I encountered a problem when using the find command:
The problem is that I want to use the find command to find the log file created five days ago under/var/log, and then delete it.
I wrote this on the terminal:
Find/var/log-name "*. log"-depth-ctime + 5-exec rm {}\;
A warning is displayed as soon as the migration is complete:
Find: Warning: You have defined the-depth option after the non-option parameter-name, but the option is not a Location Option (-depth affects the specified comparison test before or after it ).
Specify the option before other parameters.

Do you have to pay attention to the location of the depth parameter?
I am not very grateful to have a high finger.