In this video, we review adding and removing elements in more detail.
using div elements can be helpful when adding/removing many child elements.
div.children.remove(name_of_element). Remember, you need to specify the html element, not the Dart object.
div.children.removeAt(location_of_child_element_in_the_list)
div.children.removeLast() removes the last child element.
using css to hide/show elements is an option too.