Ключевые слова: 14, 314, april, background, black, calendar, chalkboard, constant, day, definition, diameter, education, equivalent, flat, formula, globe, greek, international, irrational, label, lay, letter, long, march, marketing, math, mathematical, mathematics, minimalism, notice, number, page, paper, pastry, physics, pi, reminder, row, school, science, sign, stand, student, symbol, text, top, treat, view, white, word,