Ruler by Steps (RbySteps): Exploring Length Measurement with Young Children Through a Sequential Ruler Construction

Abstract Measuring lengths with a ruler poses a challenging task for young children, who often struggle with issues related to identifying the unit on the measuring instrument and interpreting the starting point of the measurement. This study introduces RbySteps, a didactic sequencing proposal designed to address these difficulties by simulating the step-by-step construction of a ruler, significantly including the elements of the ruler: numbers, marks and units. A total of 36 children enrolled in the final year of early childhood education (5–6 years old) participated in the study, of whom 19 were assigned to an experimental group and utilized RbySteps, while the other 17, constituting the control group, followed a conventional length teaching format. Following the intervention, the experimental group demonstrated enhanced proficiency in measuring lengths with a ruler, whereas the control group showed no similar improvement. This leads to the proposal of a Hypothetical Learning Trajectory (HLT) for length measurement with a ruler based on RbySteps.