Handling multiple checkboxes that have different id and functions

What would be the best way to put all the checkboxes in a single event?

Example is the code below, and I have 20 of it (from #tcbx1- #tcbx20).

function tblcheckboxes(){
    var a=0;
    if ($('#tcbx1').is(":checked")) {
         a = parseFloat($("#tcbx1").val(), 10);
    }

$(document).ready(function(){
        $('#tcbx1').click(function(){
            tblcheckboxes();
            grandtotal();
        });
});

And another checkbox that has a different id and different $(document).ready(function(){ (from #cbx3- #cbx5)

function grandtotal(){
    var g=0;
    if ($('#cbx3').is(":checked")) {
        g = parseFloat($("#cbx3").val(), 10);
        }

$(document).ready(function(){   
    $('#cbx3').click(function(){
        grandtotal();
});

The first checkbox is grouped in a single table and the other checkbox are just some add-ons.