The researcher used self-constructed problem-solving and problem-posing activity sheets to ask students to do solving and posing by themselves, then discuss together afterwards. When teaching was completed each time, the researcher asked students to write learning diaries. The researcher referred to the students¡¦ records on problem-solving and on problem-posing and analyzed the categories of students¡¦ work and the contents of posing problems that students created as well as problem-solving strategies. He also referred to students¡¦ learning diaries to investigate into students¡¦ reflections on their problem-posing, and to make a record of self reflections during his problem-posing activities implementation. The results of this research showed that most of the students given problems included sufficient data for problem solving. Students virtually were able to make feasible problems but only few students can change the structures of the original given problems. Most of these problems are ¡¥Exchange problem¡¦ which be solved correctly by themselves. Most students solved problems by using the strategy relating to Multiples. The most important factor for accuracy and solving strategy is number type on the proportion problems. Moreover, students expressed that they were able to acquire study methods and have great enjoyment from problem-posing. Also, the teacher found that during problem-posing, students will advance in thinking and creativity.