Ключевые слова: academic, analyzing, attention, blackboard, board, campus, chalk, chalkboard, class, classroom, college, communication, concept, detail, discussion, education, engaged, explaining, explanation, expression, focus, gesture, highschool, informative, instruction, knowledge, learning, lecture, lesson, math, mathematic, note, pointing, professional, professor, school, serious, student, subject, teacher, university, visual,