In the effort to upgrade teachers' as well as pupils' mathematical competence, the University of thePhilippines National Institute for Science and Mathematics Education Development (UP NISMED)spearheaded the most number of teacher trainings in the Philippines. This paper reports a study carriedout to investigate if there is a relationship between the teachers' personal characteristics and the teachers'mathematics achievement as well as the improvement of their instructional skills as a result of the train-ing they participated in under UP NISMED's in-service program. It also describes the heart of the in-ser-vice program that devoted to reinforcing the use of Practical Work as a springboard to developingunderstanding of mathematical concepts. This is in keeping with the time-tested principle "hands-on,minds-on and hearts-on" approach.