private static Double doCalculate(Double result, BOEnum operation, Number operand) {
		switch (operation) {
		case ADD:
			result += operand.doubleValue();
			break;
		case DIVIDE:
			result /= operand.doubleValue();
			break;
		case MULTI:
			result *= operand.doubleValue();
			break;
		case SUB:
			result -= operand.doubleValue();
			break;
		default:
			throw new RuntimeException("Not supported operation");
		}
		return result;
	}