JSFiddle - React, Tailwind, and code Playground

HTML

<div id="links">
    <a href="#" num="2" class="redlink 2">2 - 8</a>
    <a href="#" num="2" class="redlink 2">2 - 2</a>

    <a href="#" num="4" class="redlink 4">4</a>
</div>

CSS

a {
    display: block;
}
.redlink {
 color: red;   
}

JavaScript

(function($) {

    $('#links a').on('click', function() {
        var num = $(this).attr('num');
        
        // méthode via .class
        $('#links a.redlink.'+num).css('font-size', '20px');
        // méthode via [attribut]
        //$('#links a[num='+num+']').css('font-size', '20px');
    });

})(jQuery);