Critical thinking is basically just a way and type of thinking in some people that makes them SUPER smart and quick. Some of the mental activities involved in critical thinking are Go for Gold, Gap Fill In, Journal Data Goals, and many others.
The U.S. National Council for Excellence in Critical Thinking defines critical thinking as the "intellectually disciplined process of actively and skillfully conceptualizing, applying, analyzing, synthesizing, or evaluating information gathered from, or generated by, observation, experience, reflection, reasoning