This book contains perceptions and practices of mathematics teachers in Nepal. It describes different perceptions of mathematics teachers and their practices. This presents model practice to address critical thinking not only in mathematics but also in other subjects. The model like critical killer versus critical filler can be used in any part of the world. This book describes about different theories like Knowledge constitutive interest, activity theory and theory of expansive learning and the reflective judgment model. This book presents a model for future directions in addressing critical thinking in mathematics classroom as a vision in the field.