The importance of learning mathematics in different aspects of our lives is undeniable, we use mathematics in our lives, willingly or unwillingly, to solve various problems. Proportion is one of the most important topics in SIXTH GRADE elementary math, which in addition to helping the student solve SIXTH GRADE problems, can be used in other subjects and GRADEs, even in college. In this study, an attempt was made to answer the question, what are the best methods of teaching fraction and proportionality in the SIXTH-GRADE elementary mathematics curriculum for sustainable learning in students? The method of this research was qualitatively phenomenological. In this study, information was collected through interviews with 12 SIXTH GRADE primary school teachers in Golestan province who were selected based on purposive sampling method. The tools of data analysis in this study are open, axial and selective coding. After coding the texts of the interviews, 12 categories were extracted, which include: using plays and stories, paying attention to the teaching needs, group work, question-and-answer method and problem solving, providing purposeful teaching, media tools, combined teaching methods, drawing, using the training tools were skill-based, encouraging and exploratory. The results showed that active and combined teaching methods are effective for teaching fraction and proportionality ratio to achieve sustainable learning in students. Using these methods, students can be interested and motivated to achieve sustainable learning by focusing more on the subject.