Based on a survey of 3067 Finnish 5th and 7th graders and a task-based interview of 20 7th graders we examine student's understanding of fraction. Two tasks frame a specific fraction (3/4) in different contexts: as part of an eight-piece bar (area context) and as a location on a number line. The results suggest that students' understanding of fraction develops substantially from 5th to 7th grade. However, Part-to-Whole comparison is strongly dominating students' thinking, and students have difficulties in perceiving a fraction as a number on a number line even on 7th grade. (Contains 3 footnotes, 4 figures and 2 tables.) [For complete proceedings, see ED500858.]