Abstract: In order to investigate the representations of students of different math abilities on ill-structured word problems with question ahead of condition,eighty students in the fourth grade at a primary school in Hebei were divided into two groups by their math test scores in recent three times,and were asked to solve ill-structured mathematical word problems including irrelevant condition sentences with numbers inside respectively in two kinds of question positions to condition sentences:"before" and "after".The results showed that the high-ability subjects got significantly higher scores,took significantly less time on reading condition sentences,larger ratio of time on reading relevant conditions to time on reading all conditions,and less time on resolution in the "before"question position than in the "after"question position,while the low-ability subjects did not get significantly higher scores,and took significantly smaller ratio of relevant reading time to total reading time in "before"question position than in "after " question position although both the total reading time and resolution time were significantly less in "before"than in "after".The results meant that high-ability subjects constructed problem model and situation model on ill-structured word problem with "before"question position,while low-ability subjects merely constructed problem model.

Key words: primary school student, math ability, ill-structured word problem, problem model, situation model