Wanty Widjaja, Kaye Stacey and Vicki SteinleThis paper explores misconceptions revealed when pre-service teachers locate negative decimals on a number line. Written responses from 96 pre-service teachers to tests and group worksheets and video-recorded observation of their classroom discussions and interviews provide extensive data. Three misconceptions are identified. Two relate to incorrect analogies between the positive and negative parts of the number line. The other is a ‘repair’ to overcome an inconsistency, made more likely by intuition that negative decimals are very small. Implications for teaching are drawn.