Ключевые слова: arrow, beauty, black, blackboard, board, business, chalk, chalkboard, chart, city, class, classroom, commitment, concept, diagrams, drawing, economics, education, equation, female, girl, graph, growth, hand, increasing, learn, lesson, math, mathematical, people, person, plans, presentation, purpose, school, science, sketch, smile, student, success, teach, teacher, university, unknowns, white, woman, words, write,