The article describes the process of developing as well as evaluating the effectiveness of module in identifying levels of numeracy understanding among students in School for Hospitalized Children (SDH). The development process involves the preparation of materials, expert review and content evaluation of the module. During the development process, the module is reviewed by four experts from numerous field of study. Some suggestions has been identified and improvements has been made based on the suggestions provided. The refined module was assessed for accuracy by 20 evaluators, consisting of four experts from the same field of study and 16 SDH teachers. The results showed that the development of modules that were based on needs analysis, theory, literature review and curriculum review plays vital roles in producing a comprehensive module. All the information collected has led to the establishment of more knowledge-based modules. In general it was found that; needs analysis is necessary in order to produce modules that can be used by teachers, the process of developing modules should take into consideration on the combination of several theories in order to produce a comprehensive knowledge-based module, literature review also provides important information in producing child-centered learning activities, curriculum review is crucial in creating teaching and learning activities that meet the curriculum objectives finally, the results of the expert review from various fields of study have provided a wealth of information in theory and practice. Module assessments performed by both experts and users are also essential in producing modules that are well-researched and user-friendly