Send value from view to method and vice versa

Hi!

I need send value from view to function in controller and return to view.
Example on code:

VIEW:

PHP Code:

echo 'Count: ' . AddNumber(2); 


CONTROLLER:

PHP Code:

function AddNumber($value) {
   $NewValue = $value*2;
        
   return $NewValue; // = 4, pass this to view again in the same place
}