This book highlights the essence of quality instruction when it comes to the teaching of mathematics. The world over, it has become necessary for schools to make extensive and deep efforts to rethink their instructional programmes. This academic work was necessitated by indicators on school performance and teaching which revealed largely unacknowledged problematic teaching of mathematics in the great majority of South African schools. The book therefore is a contribution towards rethinking the teaching strategies within mathematics classrooms. The use of visualisation processes was examined in order to understand how these interact with the pedagogy of selected mathematics teachers when they teach number sense after participating in an intervention programme. This study argues that the effective use of visualisation processes enhanced the teaching of number sense.