somador2

<html>
    <head>
        <title>Bootstrap Example</title>
        <meta charset="utf-8">
        <meta name="viewport" content="width=device-width, initial-scale=1">
        <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css">
        <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
        <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.7/umd/popper.min.js"></script>
        <script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.3.1/js/bootstrap.min.js"></script>
      </head>

<body>
    <div class="container">
    <form action="processamento.php" method="post">
    Numero 1 <input type="text" name="n1" required ><br>
    Numero 2 <input type="text" name="n2" required ><br>
    <input class="btn btn-primary" name="operacao" type="submit" value="+">
    <input class="btn btn-success" name="operacao" type="submit" value="-">
    </form>
</div>
    </body>
    </html>


<html>
<body>
<?php
function somar($a,$b) {
    return $a+$b;
}

function sub($a,$b) {
    return $a-$b;
}

$v1 = $_POST["n1"];
$v2 = $_POST["n2"];
$operacao = $_POST["operacao"];
$soma = $v1 + $v2;
if($operacao == "+"){
    $soma = somar($v1, $v2);
    echo $v1." ".$operacao." ".$v2." = ".$soma;
}
if($operacao == "-"){
    $resultado = sub($v1,$v2);
    echo $v1." ".$operacao." ".$v2." = ".$resultado;
}

?>

</body>
</html>