How to change specific column of a table using CSS/Jquery

Using CSS:

table tr td:first-child + td + td {...} /* third column */
table tr td:first-child + td + td + td {...} /* fourth column */
table tr td:first-child + td + td + td +td {...} /* fifth column */

Using Jquery:

$(function() {

    $('td:first-child').addClass("firstChild");

    $(".table-class tr").each(function() {

        $(this).find('td:eq(1)').addClass("secondChild");

        $(this).find('td:eq(2)').addClass("thirdChild");

    });

});