**Effectiveness of Learning Cycle 5E Learning Model through a Contextual Approach to Mathematical Critical Thinking Skills of Grade X SMA Negeri 1 Lambandia**

**ABSTRACT**

** ^{1}**Riskawati

**Mashuri, Sufri**

^{2}**Tahir**

^{3}This research is experimental research with the aim to find out whether the implementation of *Learning Cycle 5E *learning model is more effective than conventional learning model of mathematical critical thinking ability of class X students of SMA Negeri 1 Lambandia.

The population in this study is the entire class X SMA Negeri 1 Lambandia academic year 2016/2017 spread in 3 classes with the number of 81 students. Sampling was done by using Cluster Random Sapling technique, obtained by two research classes, that is experiment class and control class. The sample of the research from both classes amounted to 54 people. This data collection technique uses to test and observation techniques. Data analysis techniques use descriptive statistics and inferential statistics.

The results of empirical research (descriptive) indicate that; (1) Mathematical critical thinking ability of experiment class students (X.2) taught using *Learning Cycle 5E *learning model consisting of 27 students showing minimum value 41, maximum score 54, mean 44,96, variance 11,499, and standard deviation 3,391; (2) students’ critical mathematical thinking skills (X.3) taught using a conventional learning model consisting of 27 students showing a minimum value of 35, a maximum value of 46, a mean of 41.74, a variance of 8.123, and a standard deviation of 2,850; and (3) the average percentage of teacher activity and student activity in the class using *Learning Cycle 5E *learning model is 77% and 76,66%, respectively. While the average percentage of teacher activity and student activity in classes taught by conventional learning model are 76, 33% and 71,33% respectively.

Inferential research using t-test has been obtained significant value = 0,000 <α = 0.05 indicates that H0 rejected and H1 accepted, so it can be concluded the implementation of *Learning Cycle 5E *learning model is more effective than conventional learning model of students’ mathematical critical thinking skills class X SMA Negeri 1 Lambandia.

**Keywords:** Critical Thinking Ability, *Learning Cycle 5E *(LC 5E)