Command bot !calc

case 'calc':
    /* Command created by iZerang */
    // !calc [numero] [x / + -] [numero 2]
    if ( is_numeric( $message[1] ) && is_numeric( $message[3] ) ) {
    switch ( $message[2] ) {
    case "*":
    case "x":
    case "X":
    $x = $message[1] * $message[3];
    $this->sendMessage("{$message[1]} x {$message[3]} = {$x}");
    break;

    case "+":
    $x = $message[1] + $message[3];
    $this->sendMessage("{$message[1]} + {$message[3]} = {$x}");
    break;

    case "/":
    $x = $message[1] / $message[3];
    $this->sendMessage("{$message[1]} / {$message[3]} = {$x}");
    break;

    case "-":
    $x = $message[1] - $message[3];
    $this->sendMessage("{$message[1]} - {$message[3]} = {$x}");
    break;
    } //$message[2]
    } //is_numeric( $message[1] ) && is_numeric( $message[3] )
    else {
    $this->sendMessage( 'Você deve digitar uma conta valida' );
    }
    break;