This paper reports how 30 experienced and competent Singapore secondary mathematics teachers attempted to imbue desired attitudes in their students and some possible factors that might have influenced the teachers' choice of instructional approaches. It was found from the analysis of lesson observations of these teachers that most of those teaching lower-ability students tended to build their students' confidence and perseverance, while those teaching higher-ability students were more inclined to help their students appreciate the relevance of mathematics. Only a minority of the teachers tried to make lessons fun by using mathematics-related resources or telling non-mathematics-related jokes. It was also discovered from the teacher interviews that two factors appeared to influence the teachers' choice of the types of positive attitudes to develop in their students: the abilities of their students and the beliefs of the teachers on what mathematics is. [This paper is the third in a symposium of four papers. For the first paper "Models of Mathematics Teaching Practice in Singapore Secondary Schools," see ED616186. For the second paper "An Experienced and Competent Teacher's Instructional Practice for Normal Technical Students: A Case Study," see ED616178. For the fourth paper "Singapore Mathematics Teachers' Design of Instructional Materials," see ED616188.]