I introduced division by reading the story The Doorbell Rang. In the story, a mother makes her two children a dozen cookies. After the children divide the cookies, the doorbell rings. Cousins and neighbors continue to join them and they divide the cookies by three, four, six and then twelve. Finally, they each have one cookie, but the doorbell rings again.
Play these fun interactive games to practice division. There are some advertisements on these sites.
We learned that sometimes a group cannot be divided equally and that we may have some left over (a remainder). The children enjoyed the story A Remainder of One.
We used magnets, counters, and unifix cubes to divide sets into equal smaller groups. Division is repeated subtraction.