Laravel call function from another class

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1<?php
2
3namespace App\Http\Controllers;
4
5use App\Http\Controllers\Controller;
6use Illuminate\Http\Request;
7
8class ChildController extends Controller
9{
10    
11    /**
12     * Common function using on multiple controller
13     */
14    public function Calculation($firstNumber, $operator, $secondnumber){
15
16        if($operator == '+'){
17            $response = $firstNumber + $secondnumber;
18        }elseif($operator == '-'){
19            $response = $firstNumber - $secondnumber;
20        }elseif($operator == '*'){
21            $response = $firstNumber * $secondnumber;
22        }elseif($operator == '/'){
23            $response = $firstNumber / $secondnumber;
24        }
25        
26        return $response;
27    }
28
29}

Copy 
1<?php
2
3namespace App\Http\Controllers;
4
5use App\Http\Controllers\Controller;
6use Illuminate\Http\Request;
7use App\Http\Controllers\ChildController;
8
9class ParentController extends Controller
10{
11    protected $ChildController;
12    public function __construct(ChildController $ChildController)
13    {
14        $this->ChildController = $ChildController;
15    }
16
17    /**
18     * Parent function using child function
19     */
20    function calc(Request $Request){
21
22        $firstNumber = $Request->input('firstNumber');
23        $operator = $Request->input('operator'); 
24        $secondnumber = $Request->input('secondnumber');
25
26        $response = $this->ChildController->Calculation($firstNumber, $operator, $secondnumber);
27        return $response;
28    }
29}