btn-group not working (group button)

[saghian]

Dear Morteza
i want create a group button such as below picture:

but group button not working:

my code:

<div class="btn-group ">
    <a href="#" class="btn btn-default">1.000.000 تومان</a>
    <a href="#" class="btn btn-primary">
      <span class="glyphicon glyphicon-shopping-cart"></span>
       خرید
   </a>
</div>

Bootstrap sample code does not work:

<div class="btn-group" role="group">
     <button type="button" class="btn btn-default">Left</button>
     <button type="button" class="btn btn-default">Middle</button>
     <button type="button" class="btn btn-default">Right</button>
</div>