In rhyming text young readers are introduced to the world of currency and coins, and more subtly, to the economic concepts of value and compensation. In this new series called "Math is CATegorical," the popular cats from the "Words are CATegorical" series show how to combine bills and coins of various denominations in order to pay for goods and services. Each of the cats enters a dollar store with a dollar in coins in a variety of combinations. There is a brief discussion of paying for things with either coins or bills or a combination and there is a nice reminder that "Money is not magical. It doesn't grow on trees." The illustrations clearly show what common coins and bills look like. This title makes a nice companion to Tana Hoban's excellent 26 Letters and 99 Cents or to David M. Schwartz's classics How Much is a Million and Millions to Measure. The illustrations are reminiscent of Mercer Mayer's "Little Critter" books and younger readers will enjoy looking at them as much for the illustrations as for the information.