As they consider sorting their rock collection by color, size, type, and hardness, Josh and Amy learn that the same objects can be organized in many different ways.

Simple text, photographs and illustrations introduce the concept of sorting objects into sets and subsets, including real-world examples of sorting.

Describes how familiar items can be sorted by color, shape, or size.

Learn what sets are and what things often go in sets.

Photographs illustrate groupings of objects in larger and smaller numbers.

Illustrates the concept of finding common characteristics between different things to form sets.