Route with controller action always throwing syntax error during Laravel Packages development

I am new in laravel package development.Just trying to develop a simple package following the below tutorial:

http://ift.tt/2lCvNtE

Everything is going well but some problem is arising when trying to add route with controller. Follownig route is working well .

Route::get('calculator', function(){
    echo 'Hello from the calculator package!';
}); 

But,the Routes given below is throwing " `

syntax error, unexpected 'Route' (T_STRING)" error.

`

Route::get('add/{a}/{b}', 'Devdojo\Calculator\CalculatorController@add');
Route::get('subtract/{a}/{b}', 'Devdojo\Calculator\CalculatorController@subtract');

Please anybody help me. Sorry for my weak English. Thanks in advance.

via Chebli Mohamed