Examining the impact of Zambia’s curriculum in outcome-based education on cognitive development: insights from mental number line research

Purpose This study explores how Zambia’s outcomes-based education (OBE) curriculum supports the development of a mental number line, which is a fundamental concept for numerical understanding. It also examines the relationship between mental number line development and students’ calculation abilities, identifying key issues that must be addressed to enhance numeracy skills. Design/methodology/approach A mixed-methods approach was adopted, combining the quantitative analysis of mathematical tests with qualitative observations of number line estimation tasks. Data were collected from 149 valid responses from Grade 6 and Grade 7 students in Southern Province, Zambia. Participants completed a test on four arithmetic operations with whole and decimal numbers and a 0–100 number line estimation task. Mental number line accuracy was assessed using the Percentage Absolute Error (PAE) and analysed using proportional judgement and estimation strategies. Findings The findings indicate that most students struggled with accurate mental number line representation. While estimation accuracy improved with grade level, many relied on counting or integer-based reasoning, demonstrating a limited conceptual understanding of numerical magnitude. No significant correlation emerged between mental number line representations and math performance, suggesting that computational skills depend more on procedural learning than on conceptual understanding. These findings suggest that the current curriculum does not sufficiently support cognitive development in numeracy. Originality/value This study underscores the importance of fostering students’ cognitive development by using an outcome-based educational approach. It emphasises the significance of student-centred resources in boosting numerical understanding and the formation of mental number lines, thereby enhancing mathematics instruction across various learning settings.