The study sought to identify students' competence with two basic linear measurement tasks. The sample comprised 1,920 students in Standards 2, 3, and 4 (ages 8–10 years) in primary schools. Through error analysis of the tasks, responses which characterized the tasks were identified. These formed the bases for the task protocols which were used to score students' work. From the data it became evident that Standard 2 students (8-year-olds) did not have the skills as identified in the curriculum objectives. Students in Standard 3 (9-year-olds) and Standard 4 (10-year olds) showed improvement but did not display mastery. Some gender differences were observed in types of responses which students made. The results have implications for curriculum monitoring. Moreover, teachers and curriculum developers should be sensitive to the impact of varying task demands on different groups of learners at the primary level. In addition, the task protocols could inform the planning of instruction.