Ключевые слова: addition, air, amusement, arithmetic, baby, block, child, childhood, childish, cube, development, digit, education, entertainment, equation, equipment, example, exercise, figure, fun, game, kid, learning, leisure, lesson, math, mathematics, number, outdoors, people, playground, preschool, problem, school, solving, study, studying, sum, teaching, toy, training, wood, yellow,