We skipped Six and saved it for after Seven in order to introduce "doubling." Again, we looked to nature, this time to find double three's. Insects have pairs of three legs. A pair of clover has six leaves. The Star of David has two triangles.
We got out our counting stones and played with doubling numbers. I would tell him to count out two rocks, and then I would ask him to double that. Four! Then, count out five rocks. Double that. 10!