$(document).ready(function() {
    // array of numbers, it's pretty redundant, there will never be more than 30 containers
    var arr = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9 , 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30];
    // hide all containers first
    jQuery.each(arr, function() {
        $('.toggle-container').hide();
    });
    // now the toggle buttons
    jQuery.each(arr, function(index, item) {
        $('#toggle' + item).click(function() {
            // this line is not working
            $('#toggle' + item + 'Container').slideToggle('slow');
            // and this just changes the toggle button from + to -
            if ($(this).html() == '+') {
                $(this).html('-');
            } else {
                $(this).html('+');
            }
        });
    });
});