Using | pipe character from a $variable makes it treat as just another argument in bash; how to escape it?

I have a bash script like this

export pipedargument="| sort -n"
ls $pipedargument

But it gives the error

ls: |: No such file or directory
ls: sort: No such file or directory

It seems to be treating the contents of "| sort -n" as just an argument passed to ls.

How can I escape it so that it's treated as a regular piped command?

I'm trying to conditionally set the $pipedargument. I guess I could just conditionally execute different versions of the command but still wondering if there's a way to make this work like above?