<div class="container">
  <div class="row">
    <div class="col-4">
      <div class="card">
        <div class="card-header">
          Calculo de Promedio
        </div>
        <div class="card-body">
          <blockquote class="blockquote mb-0">

            <form>
              <div class="form-group">
                <label for="exampleFormControlInput1">Ingrese nota 1</label>
                <input type="text" class="form-control" placeholder="ingrese su primer nota">
              </div>
              <div class="form-group">
                <label for="exampleFormControlInput1">Ingrese nota 2</label>
                <input type="text" class="form-control" placeholder="ingrese su segunda nota">
              </div>
              <div class="form-group">
                <label for="exampleFormControlInput1">Ingrese nota 3</label>
                <input type="text" class="form-control" placeholder="ingrese su tercer nota">
              </div>
              <div class="form-group">
                <label for="exampleFormControlInput1">Ingrese nota 4</label>
                <input type="text" class="form-control" placeholder="ingrese su cuarta nota">
              </div>

              <button type="button" class="btn btn-success">Calcular Promedio</button>
            </form>

            <footer class="blockquote-footer">Para mejorar su promedio debe <span class="badge badge-danger" > ESTUDIAR Y PRACTICAR </span> </footer>
          </blockquote>
        </div>
      </div>
    </div>
  </div>
</div>