Suitable for use even in demanding environments - With this water- and dust-resistant calculator, there's no need to worry about exposure to water, dust, or grime | Recommended for use even at open-air markets, street stalls, and other outdoor businesses and at shops that sell fresh food | Easy calculation of cost, selling price and margin | Automatic calculation of price plus tax, price less tax, discount, selling price, tax amount, discount amount, and margin amount | Calculate the cost, selling price, or margin of profit on an item, given the other two values | Solar powered when light is sufficient, battery powered when light is insufficient | A symbol (+, -, x, ) on the display indicates the status of operation you are currently performing | Key operations are stored in a buffer, so nothing is lost even during high-speed input | Large, easy-to-read display | Designed and engineered for easy operation | Profit margin percent '%' key gives quick access to prices and profits, and also delivers add-ons, discounts, ratios and increase/decrease values