This practical guide for teaching numeracy to children with a developmental disability is based on core concepts from the landmark Mathematics Recovery® text Teaching Number (aka 'the green book') that have been adapted for children with developmental disabilities. It sets out key principles of teaching and learning underpinning an evidence-based teaching approach and provides clear guidance on how educators can plan and implement a structured teaching program so that every child can be given a positive experience in learning numeracy and achieve significant outcomes, maximizing their potential. The book is supported by a comprehensive set of online resources for use in the classroom, including 90+ lesson plans carefully tailored to provide sequenced learning experiences for children and school students who may need them most.