Figure 5: Samples of guess-check strategy
At the beginning of the experimental application student did not prefer to use the guess-check strategy. Students were also inadequate in estimation. When students were offered to use estimation to solve the problems, some of them responded “So do you want me to make it up?” For this reason first of all it was aimed to teach estimation ability. In time, students were able to use the estimation-control strategy. It was clearly seen that student skipped the estimation step and pretended that they made an estimation by saying the exact result after solving it. This situation was an obvious sign that student in experiment group were insufficient, and classroom application was not effective. According to a research done by Faubion (2001), guess-check strategy is found and learnt difficult by students.