import static java.lang.Math.floor; public class Formatter { static String formatSum(double sum) { int intSum = (int) floor(sum); String currency = switch ((intSum <= 20) ? intSum : (intSum % 10)) { case 1 -> "рубль"; case 2, 3, 4 -> "рубля"; default -> "рублей"; }; return String.format("%.2f", sum) + " " + currency; } }