Ключевые слова: background, balance, black, business, button, calculating, calculator, calculus, checkout, clicks, clock, code, computer, count, countdown, counter, customer, digital, display, equipment, figures, finance, gray, hand, industry, instrument, isolated, key, machine, mathematical, mathematics, measurement, metal, nobody, number, object, push, sign, silver, single, small, sport, store, subtraction, tally, technology, time, two, voting, white,