Explain why, when creating a file in a Unix-like system, its default permissions are set to 666.

In Unix-like systems, when creating a file, the default permissions are set to 666 (rw-rw-rw-), which means the file is accessible for reading and writing by all users. This is the basic value, which is then modified using the umask mask to restrict access rights. This scheme allows the system to set the most open rights initially, and then narrow them down depending on the security settings of the user or system.