| In a major review of research literature on the learning and teaching of estimation, two issues were identified to serve as a basis for the current study. The first related to the need to characterize preservice teachers' thinking with regard to computational estimation, employing a developmental process of clustering the data, developing descriptors, and correlating cluster descriptors to the descriptors of the levels of the Estimation Thinking Framework. The second focused on analyzing change in preservice teachers' thinking with regard to estimation. The study was qualitative in nature and utilized case study methodology. Five preservice teachers were selected for in-depth case studies.;The current study demonstrated that the Volkova (2005) Estimation Thinking Framework can be used to characterize preservice teachers' thinking in computational estimation. The framework descriptors adequately categorized preservice teachers' responses in a systematic manner. Further, the framework was successfully used for analysis of change in preservice teachers' thinking in estimation with regard to whole numbers, fractions, decimals, and percents after the preservice teachers' participation in a course designed to focus on mathematical problem solving and reasoning with understanding of numbers and their properties. The results of the study showed that despite the absence of structured instruction specifically targeting estimation, preservice teachers improved their ability to estimate, which was confirmed by the progression of their responses from lower to upper levels of the Estimation Thinking Framework. |
