This paper aimed to develop the open-ended mathematics assessment items practicable indeed and the scoring rubrics. To that end, it previously analyzed the status of the utilization of mathematical assessment items and complemented the limitations thereof. It then defined the procedure of developing the open-ended problems and scoring rubrics suitable for the 5 sections for 5th grade elementary students under the 7th mathematical curriculum.
The analysis of the status of using the open-ended problems in elementary school confirmed that the open-ended problems were rarely used. In fact, the open-ended problems showed 1.88% on average in the use for achievement assessment and 3.01% for regular assessment. when the open-ended problems are developed, a variety of their types must be utilized. It is preferential to set the units appropriate for open-ended problems through a review of their contents. If the item developer creates the scoring rubrics to assess the mathematical process when developing the items, the rubrics would be utilized in the field as they may reduce the burden of teachers in assessing the mathematical process being increasingly important, as well as in scoring the open-ended problems. If the open-ended problems continue to be developed and are used in schools, it will facilitate assessing students’ mathematical thinking skills and have a positive effect on students.