I have taught several primary and secondary school kids who were not much interested in the subject by first aiming at changing their notion. I use several real life examples and design activities inspired by our day to day life(for example the concept of division can be taught by doing a role play of splitting people I no teams or splitting choclate by repeated subtraction amongst a group of children) to gain their interest. Then I slowly work towards the curriculum. I personally believe that Math is a fun subject as long as the concept registers in your mind hence I work towards clearing the concepts for the students.