Each read-aloud book in the Mouse Math series focuses on a single, basic math concept and features adorable mice, Albert and Wanda, who live in a People House. Entertaining fiction stories capture kids' imaginations as the mice learn about numbers, shapes, sizes and more. Over 3 million copies sold worldwide! Mouse mummies, fossil-digging, and more! Albert is excited to explore the mouseum. But when his friend Leo's little cousin goes missing, tracking her down takes the mice on a whole new adventure. Every Mouse Math title includes back matter activities that support and extend reading comprehension and math skills, plus free online activities. (Math concept: Left/Right)