The relevance and social demand for developing methods for measuring the accuracy of representation of quantitative information are associated with the need to analyze specific cognitive functions that underlie individual differences in speed and quality of learning in school. Expressed in symbolic, non-symbolic and mixed formats, representation of quantity is one of the most important cognitive functions that determines the success of learning mathematics. The article presents the results of the development and adaptation of three tests – “Number Sense”, “Number Line” and “Dot Number Task” – that measure the accuracy of the representation of quantitative information presented as sets of objects, numbers, and their combinations. The total number of study participants involved in the process of test adaptation amounted to 1,751 students in grades 1–11 aged from 6.8 to 18.8 years, of which 48.8% were girls. For each test, an internal consistency analysis was carried out, descriptive statistics were calculated, and the distribution of indicators of quantity representation accuracy at various levels of general education was analyzed. The results of the analysis showed satisfactory psychometric characteristics of computerized tests, which indicates their reliability and makes them suitable for application at the primary, basic and full levels of general education.