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, maximising 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.