One of the very-closed mathematical concepts to us is percentage, of which the idea is represented in such common forms as discount, interest in bank, battery, polling result, and some other social activities. This familiarity would be a great potential to bridge students to learn the concept using PMRI (Pendidikan Matematika Realistik Indonesia) learning approach.
Therefore with, my friend and I have tried to design a set of activities to encourage students’ understanding regarding the concept. The design has been tried out to Grade V-E students of SD Pusri Palembang.
The first activity was conducted to identify how closed the concept of percentage to students is. To begin with, we showed a tagged paper ‘50%’ and asked the students where they use to meet such writing. Almost all the students answered ‘discount’. Several other answers like ‘battery’ and ‘polling result’ was also mentioned.
Representation of percents in real life
At last, the teacher led the students to think of the representation of percent applied in ‘Pemilukada Palembang’, the just-held event in their city and guided them to term ‘surveyor’ and ‘repondent’.
In the second activity, the teacher divided the students into six groups consisting of 5 to 6 members. From each group, two students were asked to act as surveyors whose task is to gather data from the remaining students playing as respondents. Afterward, the teacher gave check-list questionnaire to student-surveyors as a tool for data collection.
Questionnaire used by student-surveyors to collect data
(due to space, some parts are cut)
During the activity, the students were really totally doing their own roles. The classroom was very crowded but still in control untill 10-minutes allocated time ended. By the end of the activity, the students were asked to work on the data by following the guideline given in the worksheet.
The students were playing ‘surveyor-respondent’ role
(green labeled for surveyor and the yellow one for respondent)
In the third activity, the students tried to represent the data they collected into 2×10 grid tables, and then convert it into the 10×10 table (they were also asked to write down the fraction which corresponds with the grid table). This guided them to think of equivalent fractions.
Example of students’ answers
Most of the students could successully convert the grid from the first into the second table. Only one group (b) failed to perform the skill since they might work less thoroughly.
The last activity was to encourage students into a formal way of converting the fraction form into percent. Here, the students discussed the way by considering the previous case (grided table). Some guidances were sometimes given by the teacher.
Here, the following, were the examples of students’ conclusions on the way of changing a fraction into percent.
Finally, due to the exercise result, we found most of the students could perform the task of converting fractions into percentages. The mistakes made were mostly ‘syntaxis error’ (wrong in notating percentage). This might be caused of the lack of emphasis in how to write the symbol of percent ‘%’. The finding, then, for us to reflect.