private String tenthPart(int number){
        StringBuffer buffer = new StringBuffer();
        if(number != 0){
            if(number <= 19){
                buffer.append(toString(number));
            }else{
                int first = (number/10)*10;
                int second = number%10;
                buffer.append(toString(first));
                if (second != 0){
                    buffer.append(toString(second));
                }
            }
            return buffer.toString();
        }else{
            return "";
        }
    }
Convert a number into words

Reference
https://leetcode.com/problems/integer-to-english-words/
src/com/interview/misc/NumberToWord.java