<div class="container">
  <div class="row">
    <div class="col-xs-4 col-xs-offset-4">

      <div class="calculator">
        <div class="row">
          <div class="col-xs-12">
            <h3>
            JavaScript Calculator
          </h3>
          </div>
        </div>
        <div class="row">
          <div class="display col-xs-10">
            <div class="row">
              <label class="result col-xs-12" data-bind="text: truncatedResult"></label>
              <label class="calculation col-xs-12" data-bind="text: truncatedCalculation"></label>
            </div>
          </div>
        </div>

        <div class="row button-row">

          <div class="col col-xs-3">
            <button class="btn btn-default btn-ce">
            CE
          </button>
          </div>

          <div class="col col-xs-3">
            <button class="btn btn-default btn-clear">
            C
          </button>
          </div>

          <div class="col col-xs-3">
            <button class="btn btn-default">
            ÷
          </button>
          </div>

          <div class="col col-xs-3">
            <button class="btn btn-default">
            x
          </button>
          </div>

        </div>
        <div class="row button-row">

          <div class="col col-xs-3">
            <button class="btn btn-default">
            7
          </button>
          </div>

          <div class="col col-xs-3">
            <button class="btn btn-default">
            8
          </button>
          </div>

          <div class="col col-xs-3">
            <button class="btn btn-default">
            9
          </button>
          </div>

          <div class="col col-xs-3">
            <button class="btn btn-default">
            -
          </button>
          </div>

        </div>
        <div class="row button-row">

          <div class="col col-xs-3">
            <button class="btn btn-default">
            4
          </button>
          </div>

          <div class="col col-xs-3">
            <button class="btn btn-default">
            5
          </button>
          </div>

          <div class="col col-xs-3">
            <button class="btn btn-default">
            6
          </button>
          </div>

          <div class="col col-xs-3">
            <button class="btn btn-default">
            +
          </button>
          </div>

        </div>
        <div class="row button-row">

          <div class="col col-xs-3">
            <button class="btn btn-default">
            1
          </button>
          </div>

          <div class="col col-xs-3">
            <button class="btn btn-default">
            2
          </button>
          </div>

          <div class="col col-xs-3">
            <button class="btn btn-default">
            3
          </button>
          </div>

        </div>
        <div class="row button-row">

          <div class="col col-xs-6">
            <button class="btn btn-default">
            0
          </button>
          </div>

          <div class="col col-xs-3">
            <button class="btn btn-default">
            .
          </button>
          </div>

          <div class="col col-xs-3">
            <button class="btn btn-default">
            =
          </button>
          </div>

        </div>
      </div>
    </div>
  </div>
</div>