I made a list of checkboxes that upon click get sent to a database. However, the only values that show in the database are 0. For example, a person can click 2 checkboxes, but the values sent to the database are 0 and 0. How can I submit the real values of the elements to the database?

Here is my code:

<form method="post">
    <?php
    
    global $wpdb;
    
    $Result = $wpdb->get_results("SELECT Product1 FROM A");
    
    foreach($Result as $Thing1) {
        echo '<input type="checkbox" name="Num1[]" />' . $Thing1->Product1 . "<br />";
    }
    
   
        $Age = $_POST['Num1'];

    if($_POST['btn']) {
        if(!empty($Age)) {
            foreach($Age as $id) {
                $Word = $id;
            // does not matter if checkbox value is 1 or 4, still goes as 0 to db
            $wpdb->query("INSERT INTO A(Product1) VALUES('$Word');");
            }
            
         }
    }
    

    ?>

    <input type="submit" name="btn" />    
    </form>