To be honest, I’m not particularly a fan of the Rookie Ready to Learn series in general:  I find the activities in the back of each are often formulaic and only tenuously related to the story; each one ends by telling you someone’s version of what you just learned by reading this story (besides being patronizing, they often don’t hit the mark).  But if you do like this kind of thing, or you’re willing to ignore the extra features that don’t enhance them, the central stories are often good little stories, with redeeming qualities of their own.  This one uses repetitive pattern, rhyming text to describe things balls do, and inviting the reader to count balls in certain illustrations.  The use of varied verbs will be useful for vocabulary development and grammar discussions.