We love Math*U*See around here. It's not very exciting but it's solid and does the job well. The older three use it and this year our first grader is using something else. However, we have been using the manipulatives that came with MUS.
Em is practicing place values here. It helps to use manipulatives like this to put into practice the problems on the page. I sat down with her on the ground and showed her how to do it. We did a couple problems together and then I let her go.
Her bigger sister couldn't wait until Em was done with her assigned problems so they could do it together. She made up problems for her little sister and they worked them out. (Ignore the two brothers and dog wrestling in the background. It was almost lunch.)
Little sister loves doing it with bigger sister. I also believe that it reinforces what Els has learned to "teach" a younger one what she knows. See, math can be fun.