/*
.removeClass( [className] ):classNameOne or more space-separated classes
to be removed from the class attribute of each matched element.
So, join all the classes you want to remove into a space separated list.
*/
var classesN = [class1, class2, class3];
var classesAlpha = [classA, classB, classC];
$('#alphas').click(function() {
$('div').removeClass(classesAlpha.join(' '));
});
$('#numbers').click(function() {
$('div').removeClass(classesN.join(' '));
});