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! While the cat's away, the mice will visit the playroom! But when all the toys come tumbling down, can Albert sort them back into the right bins before the People come home? Every Mouse Math title includes back matter activities that support and extend reading comprehension and math skills, plus free online activities. (Math concept: Sorting)