Ключевые слова: 20, 80, analysis, background, business, chalk, chalkboard, chart, class, closeup, college, color, concept, data, doing, duties, economy, education, eighty, exercise, factor, female, few, finance, financial, graph, green, hand, home, homework, idea, information, job, knowledge, law, learn, learning, lesson, majority, market, marketing, minority, number, office, pareto, percentage, person, plan, portion, preparation, principle, profit, pupil, quota, report, representation, research, result, rule, school, schoolwork, share, smart, sparsity, statistics, student, study, studying, success, survey, twenty, university, vital, wisdom, woman, word, work, working, writing,