“…To ensure the reliability of the findings, all instruments used, including test items, questionnaire sheets, and interview guidelines, were developed. The questions for measuring mathematical creative thinking ability were prepared based on indicators such as 1) thinking about more than one answer (fluency), 2) looking for several alternatives or different directions (flexibility), 3) thinking about unusual ways (authenticity), and 4) adding or breaking down the details of an idea, object, or situation to make it more interesting (elaboration) [ 19 , 33 , 34 ]. Each question represented one indicator, and for mathematical creative thinking ability test questions to be valid, reliable, discriminating, and appropriately challenging, it needs to meet certain criteria.…”