In laravel how to count table valve

i what to count each center users how mach student they registered.

i have two different table,

1st "center" 2nd "student"

1st table "Center" i have "center_id" column in that table i have ( center_id like "PP_123" ) 2nd table "student" i was created "center_id" column in that table i am saving center_id like "PP_123",

if center user registers student that time 2nd table "student" files with student data along with it stores the "center_id" in "student" table,

my controller this code only showing all centers name and id

//ACTIVITIES

          public function center_activities()
  {

        $activities_list = Center::where('center_delete','NOT-DELETED')->Where('account_type','OLD_ACCOUNT')->get();


        return view('Center.cernter_activites',compact('activities_list'));

  }

via Chebli Mohamed