Ключевые слова: baby, background, blackboard, board, calculation, chalk, child, childhood, college, color, concept, digit, dirty, draw, dust, educate, education, eight, five, hand, increase, investigate, isolate, knowledge, learn, lesson, mathematics, mesh, multiplication, multiply, nine, nobody, number, preschool, primary, school, science, seven, six, square, study, table, teach, ten, wooden,