order by multiple meta_keys?

Question

Hi i'd like to order by multiple meta_keys

want to make it order using these keys

adminscore + user_like + _count-views_all + comment_count

combine these keys how should i array order it??

i try this but not work..

  $args = array(
            'meta_key' => 'adminscore' + 'user_like' + '_count-views_all' + 'comment_count',
                'numberposts' => $number_posts,
                'post_status' => $post_status,
                'post_type' => $custom_post_type,
                'orderby' => 'meta_value_num'
               );

Thanks for check my question, hope someone has answer for it.