<form>
    <div class="form-group">
      <input type="email" class="form-control" id="exampleInputEmail1" aria-describedby="emailHelp">
    </div>
</form>

<div>
    <input class="btn btn-primary" type="reset" value="Dec ">
    <input class="btn btn-primary" type="button" value="  1  ">
    <input class="btn btn-primary" type="submit" value="  2  ">
    <input class="btn btn-primary" type="reset" value="  3  ">
</div>
<div>
    <input class="btn btn-primary" type="reset" value="Bin  ">
    <input class="btn btn-primary" type="button" value="  4  ">
    <input class="btn btn-primary" type="submit" value="  5  ">
    <input class="btn btn-primary" type="reset" value="  6  ">
</div>
<div>
    <input class="btn btn-primary" type="reset" value="Hex ">
    <input class="btn btn-primary" type="button" value="  7  ">
    <input class="btn btn-primary" type="submit" value="  8  ">
    <input class="btn btn-primary" type="reset" value="  9  ">
</div>
<div>
    <input class="btn btn-primary" type="reset" value="  +   ">
    <input class="btn btn-primary" type="button" value="  *  ">
    <input class="btn btn-primary" type="submit" value="  0  ">
    <input class="btn btn-primary" type="reset" value="   /  ">
</div>
<div>
    <input class="btn btn-primary" type="reset" value="   -   ">
    <input class="btn btn-primary" type="button" value="  = ">
    <input class="btn btn-primary" type="submit" value="   (  ">
    <input class="btn btn-primary" type="reset" value="   )  ">
</div>