num2: <input type="text" name="num2"><br> +<input type ="checkbox" name="+" value="+"><br> <input type="submit" value="Submit"> </form> <?php if(isset($POST['num1']) || isset($_POST['num2'])) { if(is_numeric($_POST['num1'])) $zmienna = $_POST['num1']; else echo 'llloooool, to nie liczba'; $zmiennaa = $_POST['num2']; if(isset($_POST['+'])) $znak = $_POST['+']; else $znak ="+"; } else { $zmienna = $_POST['num1'] = 0; $zmiennaa = $_POST['num2'] = 0; } $suma = new oop2(); echo $suma->oblicz($znak,$zmienna,$zmiennaa);