Hey, these are dancing shoes! Both: One, two, one, two, one, two, one, two. One, two, one, two, one, two, one, two. Two: Everything is better with two. The two of us ...

Doing math is thought to be a uniquely human skill. We can learn the abstract concept of a number: two things or three things or four things; we can represent that concept symbolically (2, 3, 4); and ...