<form action="procesar.php" method="get">
Primer valor: <input type="text" name="valor1" />
Segundo valor: <input type="text" name="valor2" /><br />
<input type="radio" name="radio" value="sumar" />Sumar<br />
<input type="radio" name="radio" value="restar" />Restar<br />
<input type="radio" name="radio" value="dividir" />Dividir<br />
<input type="submit" name="enviar" value="Enviar">
</form>