This study proposes a computer-assisted system with a design based on Polya's problem-solving model. The system is designed to help average and low-achieving second graders in mathematics with word-based addition and subtraction questions. The emphasis of using the specific model was on dividing the problem-solving procedure into stages and the concentration on the stages that are problematic for students. Specifically, we compared mathematical word problem-solving performance and computational skills of students who utilized the computer-assisted system with students who employed general strategy instruction. Participants consisted of 52 second-grade students randomly assigned to treatment conditions. Students were pretested and posttested with mathematical problem-solving and computation tests, and repeated measures of their progress with respect to word problem solving were registered. The results showed there was a significant difference between the experimental and control groups in terms of the word problem-solving progress measure, favouring the experimental group. This confirms that providing students with a computer-assisted system offered the opportunity to explore all stages of the problem-solving procedure as one possible way to enhance their problem-solving skills.