Ключевые слова: alternative, board, business, calculate, calculation, children, class, classroom, color, desk, development, divide, dividend, dividing, division, division board, educate yourself, education, educational, elementary, elementary school, guidance, learn, learning, material, math, mathematical, method, montessori, number, operation, preschool, primary, pupil, school, schoolchild, set, size, student, teach, technique, understanding, with e, wooden,