Ключевые слова: 14th, 3, 14, academic, arithmetic, background, blackboard, chalk, chalkboard, circle, circumference, classroom, college, constant, date, day, diameter, education, exam, explain, female, hand, homework, international, irrational, knowledge, learn, lecturer, lesson, march, math, mathematical, mathematics, number, people, person, pi, profession, ratio, school, science, student, study, subject, teacher, tutor, university, woman, world, writing,