This is such a simple and fun homeschool lesson for the little ones. While the big kids are doing lessons, I can quickly go through and give the littles a quick math lesson on my computer too. Since I can see this on my phone as well, this is a fun time waster while sitting at the doctors office or in a restaurant while waiting. My littles are always trying to be like the big kids, and giving them a lesson like this is easy for everyone, but plants the seed for more complicated math in years to come. Best part? It is FREE on Amazon Kindle right now. Score!