Most studies of children's solution processes on simple addition and subtraction word problems have used individual interviews or the analysis of error patterns on paper-and-pencil tests as the primary data-gathering techniques. The present paper reports an investigation in which the contribution of eye-movement data was explored for studying those aspects of the problem-solving process that are inaccessible with the methods mentioned above, especially the text-comprehension processes contributing to the construction of a problem representation, and the subject's decision-making processes in choosing a solution strategy. Eleven addition and subtraction word problems were administered individually to 9 high-ability and 11 low-ability first graders. For each problem, eye-movement data were collected while children read and solved the tasks; afterwards they were asked to explain verbally how they arrived at their answer. Besides the usual findings concerning problem difficulty, solution strategies, typical errors and solution times, an anlysis of the gaze durations and the sequences of fixations is presented. In addition to some interesting findings concerning solution processes, the study also showed that eye-movement registration can be used easily with young children, and is appropriate for collecting data on their cognitive processes. Five pages of references and seven data tables conclude the document. (Author/MNS)