Ключевые слова: back, background, balance, business, button, calculating, calculator, checkout, clicker, clicks, code, concept, conceptual, control, count, countdown, counter, customer, digit, digits, display, equipment, figures, finance, full, hand, hold, industry, instrument, key, machine, mathematical, mathematics, measurement, metal, number, numeral, occupation, push, roll, silver, single, small, sport, store, subtraction, technology, tool, voting, white,