Ключевые слова: adult, algebra, background, blackboard, board, calculate, casual, caucasian, chalkboard, class, classroom, college, concept, cool, desk, education, equation, fashion, female, formula, girl, handsome, knowledge, lesson, lifestyle, math, mathematical, mathematics, number, person, portrait, professor, school, science, serious, student, study, teacher, theory, trendy, trigonometry, university, white, woman, write, young,