This new entry in the Mouse Math series sends Albert to the fair, where there are plenty of opportunities to double up. His friend Leo out when Albert comes calling, the little mouse heads to the fair with big sister Wanda and buys two maps (one for Leo), ride the Ferris wheel four times--twice for himself and then twice more for Leo--wins the pie-eating contest by chowing down on three slices and then three more, and plays the ring toss until he wins the eight tokens needed for two packages of five Robo-Rat action figures. At each stop the arithmetical doubling is depicted below the simple cartoon illustrations with number sentences and iconic images of such items as tickets or pie slices. Suggestions for discussions topics and enrichment activities at the end are addressed to educators, but young readers should have no trouble themselves re-creating the paper-towel-tube ring toss that Albert and Leo set up after discovering that they had both been to the fair and now have an oversupply of Robo-Rats. Simultaneously publishing are Albert Helps Out (using coins) and Where's Albert? (skip counting), both also by May, and Bravo, Albert! (patterns), by Lori Haskins Houran.