The little ones must understand. The Almighty emphasized in the Torah that the children cannot be expected to participate in Pesach as only a "ritual" that they do not comprehend. It is essential for them to understand. Though it seems more comfortable to skirt the issue of "sacrifi ce" in our Pesach meal, it is really unavoidable. As is recorded in the Torah, it is the central focus of our festival. So, when the children ask you, the answer must be: IT IS A SACRIFICE.