Fatal error: Uncaught TypeError: Unsupported operand types: string - int in /var/www/code/app/class/Controller/Category.php:46 Stack trace: #0 /var/www/code/app/routes/main.php(41): App\Controller\Category->detail() #1 [internal function]: {closure}() #2 /var/www/code/vendor/phroute/phroute/src/Phroute/Dispatcher.php(58): call_user_func_array() #3 /var/www/code/init.php(30): Phroute\Phroute\Dispatcher->dispatch() #4 /var/www/html/index.php(2): require('...') #5 {main} thrown in /var/www/code/app/class/Controller/Category.php on line 46