The article illustrates the aspects of powerful professional learning through three pedagogical tools that emerged from a content analysis of a large data set of the Numeracy Development Project. Since 2000, more than 25,000 teachers and 690,000 students in English-medium and Māori-medium (indigenous) settings have participated in the project. The content analysis identified three pedagogical tools that participants describe as improving their mathematics knowledge and practice: the number framework; the diagnostic interview and the strategy teaching model.