Introduction. In this study, we focus on the relationship between the students' mathematical thinking and their non-mechanically identified eye-movements with the purpose to gain deeper understanding about the students' reasoning processes and to investigate the feasibility of incorporating eye-movement information in everyday pedagogy. Method. This is a quantitative study. Thirty-eight (N = 38) Grade 1 (6 years old) students were verbally presented with six word arithmetic problem: three problems of "change" and three problems of "comparison". The problems were chosen to be within the students' mathematical abilities. Results. The findings of this study appeared to validate the non-mechanical data collection technique. Furthermore, differentiations were found in the students' rightwards eye-movements (suggesting the activity of the left hemisphere) and the eye-movements spread (suggesting the activity of both hemispheres) in line with the literature. The more challenging problems were found to be linked with a wider spread of eye-movements and to be more time consuming. Moreover, though boys appeared to be faster than the girls in the easier tasks, no statistical differences were found in the more challenging tasks. Discussion. The adopted "softer" technique was sensitive enough to be in accordance with the existing literature and at the same time helped in gaining deeper understanding in the students' reasoning about "change" and "compare" problems. For example, the reported gender differences--in line with broader research evidence from education and neurophysiology--are hypothesised to indicate of qualitatively different thinking processes involved, which may be related to different gender-related thinking dispositions. Consequently, it is posited that the adopted technique was is in line with the relevant research evidence, offering at the same time insight in the complex processes involved, thus allowing for further research to be conducted in order to investigate the pedagogical benefits of the incorporation of such "softer" eye-movement identification techniques in everyday pedagogical practices.