Supervisors info:
Επιβλέπουσα: Χριστίνα Μισαηλίδου, Λέκτορας, Π.Τ.Δ.Ε., Ε.Κ.Π.Α.
Συνεπιβλέποντες: Αγγελική Βουδούρη, Καθηγήτρια, Π.Τ.Δ.Ε., Ε.Κ.Π.Α.
Γεώργιος Μπαραλής, Αναπλ. Καθηγητής, Π.Τ.Δ.Ε., Ε.Κ.Π.Α.
Summary:
The research presented in this study investigates the greek sixth graders’ performance at computational estimation problems. Moreover, this study examines the type of strategies they use when facing such problems and the difficulties they encounter.
In order to collect the necessary data, a questionnaire with ten representative word problems was designed. The computational estimation abilities were examined through the presentation of these problems and the written recording of estimations from the students, in appropriately designed response sheets with a response time limit for each problem. The questionnaire was given to 103 sixth graders from three primary schools in Athens. In order to confirm the credibility of the results, a few chosen interviews were conducted.
The performance of these students in all computational estimation problems was poor. Only 27,9% of the total results were accurate estimations. Their failure was, mostly, caused by the use of exact methods and the erroneous application of the estimation strategies.
Rounding was the most frequently used strategy by the participants. However, results indicate the tendency of students to resort to rounding whenever possible, even in cases not appropriate for the production of effective estimations. Moreover, other estimation strategies were rarely applied, while both rounding and the rest estimation strategies were mostly applied erroneously by the students. Nevertheless, the students used estimation strategies in most responses (55,8%), demonstrating that they were able to identify estimation situations. Furthermore, a significant tendency of students to exact calculations was noticed, with approximately 3/10 of total answers including exact calculations. Finally, in 1/7 of total answers, students did not use any solution method.
The most common reason for faulty responses were calculation errors both when implementing various estimation strategies and when performing accurate calculations (33%). Subsequently, incorrect application of strategies (28,2%) and students’ inability to provide an answer in certain occasions (14%) were observed.
Finally, the factors that affected the degree of problems’ difficulty were the kind of arithmetic operations required, the magnitude and type of the numerical data and the kind of context. The problems that proved to be more difficult were those that involved division or multiplication, as well as big numbers and decimals. On the contrary, the problems’ context that included money proved familiar to students and made their estimations easier.
