Ключевые слова: alternative, banking, bill, blackboard, board, bulb, business, cash, chalk, chalkboard, classroom, concept, consumption, cost, currency, dollar, eco, economic, economy, education, efficiency, efficient, electric, electricity, energy, entrepreneurship, equal, equipment, finance, financial, fluorescent, idea, innovation, investment, lamp, learning, light, lightbulb, money, note, object, organization, paper, power, roll, saving, school, sign, solution, technology,