There's lots of counting money throughout the story, mainly quarters and dollars. Every time they sell some lemonade, the older sister explains how much they made. They have to count their quarters to buy the lemons and limes, and then count again when they're done to see their profit. A final section has an explanation of coins, how to tell them apart and how they add up to dollars.
Karas' illustrations are cute, but I would have preferred something more life-like for kids learning to identify money. However, this is a good read-aloud and a few pictures on a flannel board or some real change will help the kids match and compare.
Verdict: An excellent addition to your concept books. Recommended.