How to add Google Adsense in WordPress child theme

To insert ads into a child theme on an Adsense site: add the following code to function.php:

////////////////////////
///Google AdSense:
//
add_action('wp_head', 'wpse_43672_wp_head');
function wpse_43672_wp_head(){
    //Close PHP tags 
    ?>
<script data-ad-client="ca-pub-<publisher-numberic-code>" async src="https://pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"></script>
    <?php //Open PHP tags
}
////////////////////////

Don’t forget to replace the publisher’s numeric code (also removing the angle brackets around it).

p.s.
But in general it is more convenient to insert this code through a wordpress widget 🙂