Peek-a-boo, a round-shaped penguin, invites young children into his home. The text states that he has "1 bed" and "1 teddy bear." Readers are asked to name other items that he has only one of. He has "2 pieces of toast" for breakfast with him mother. Can the reader spot other pairs of items? The concept of 3 is presented with pets. He washes dishes to show sets of 4. Mommy Penguin launders "5 T-shirts" and "5 towels." Beginning with the page for 6 items, the reader becomes involved in counting numbers of items that are less than the featured number. There are 6 striped socks on the clothesline, but only 4 red ones. Fruit salad ingredients also have groupings of various numbers after calling attention to the "7 blueberries" in a glass bowl. There are "8 bricks" shown and 8 books to count. Six yellow plastic ducks watch Peek-a-boo count nine bubbles rising from his bath. He makes "10 puddles" when he gets out of the tub. Twelve pages of learning activities reinforce the concept of counting and introduce the idea of "1 more" and "1 less." An ending page of "Notes for parents and teachers" includes suggestions for extending knowledge of numbers and counting. The brightly colored illustrations and the clearly defined directions make this a good choice for inquisitive toddlers. Part of the "Peek-a-Boo Penguin" series. Reviewer: Phyllis Kennemer, Ph.D.