Manipulatives are hands-on learning tools that help students learn concepts concretely before moving to more abstract understandings. They allow students to explore ideas through active manipulation, helping cement understandings in ways that passive learning cannot. There are concrete, abstract, and virtual forms of manipulatives, each with advantages and disadvantages. Integrating different types of age-appropriate manipulatives into lessons can benefit student learning across subjects by appealing to different learning styles and building concrete foundations for abstract concepts according to Piaget's theories of cognitive development.