Abstract: This paper is concerned with the investigation of children’s knowledge and their methods of organizing it in solving ratio and proportion problem. Strategic models which represent pupils’ approaches on solving different types of ratio and proportion problem and a generic model which explains the essential information for solving a set of ratio and proportion problem were identified. A total number of 499 children at an average age of 11 years sat for a ratio and proportion test. Analysis of their responses was carried out in 3 stages: (1) examining and recording different strategies used by problem solvers, (2) classifying the identified strategies in terms of techniques and methods used and the different steps in arriving at the answers and (3) linking procedural knowledge and conceptualizing (a) an overall strategic model used for solving ratio and proportion problem and (b) a schematic model for solving each ratio and proportion problem. The results of the study revealed the various types of strategies used by these children and the different levels of thinking employed in solving the problem. The models are presented to show the path of each strategy by connecting sets of skills of the problem solvers. The study confirm that problem solvers requires bodies of essential knowledge and well organized structure to solve mathematical problems.