Ключевые слова: algebra, background, black, blackboard, board, book, calculate, calculus, chalk, chalkboard, class, classroom, college, complex, education, equation, equations, exam, formula, geometry, homework, learn, lesson, math, mathematical, mathematics, number, pattern, perspective, physics, problem, school, science, scientific, sign, solution, student, study, studying, symbol, teacher, theoretical, theory, university, white, write,