Markdowns in percentage or moans about percentage

In previous activities we identified misconceptions of pre-service teachers about the topic of percentages (Bassan-Cincinatus & Sheffet, 2016). Consequently, we built a teaching unit based on the constructivist approach and used the cognitive conflict method. Our main objective was to assist pre-service teachers to be aware of the fact that intuitions do not always lead to the correct solution of this issue. The teaching unit consisted of six stages. This paper will describe the various stages, present the way of experiencing, the findings as well as pre-service teachers' reflection and responses following the activity.