Ключевые слова: accounting, analysis, background, balance, black, blank, budget, business, busy, button, calculate, calculating, calculation, calculator, count, data, digital, digits, document, earnings, economy, education, empty, equipment, finance, financial, grey, hand, hands, key, keyboard, management, mathematical, mathematics, memo, note, number, numerals, object, office, oldfashioned, page, paper, report, rule, ruler, school, sheet, slide, slipstick, symbol, tool, white, work,