四位数以下一般就是“几百几十几：~hundred and ~”；四位以上的从后往前数，隔三位数一逗号，这些逗号从后往前分别是thousand, million, billion。

99 ninety-nine

999 nine hundred and ninety-nine

9,999 nine thousand, nine hundred and ninety-nine

99,999 ninety-nine thousand, nine hundred and ninety-nine

999,999 nine hundred and ninety-nine thousand, nine hundred and ninety-nine

9,999,999 nine million, nine hundred and ninety-nine thousand, nine hundred and ninety-nine

99,999,999 ninety-nine million, nine hundred and ninety-nine thousand, nine hundred and ninety-nine

999,999,999 nine hundred and ninety-nine million, nine hundred and ninety-nine thousand, nine hundred and ninety-nine

9,999,999,999 nine billon, nine hundred and ninety-nine million, nine hundred and ninety-nine thousand, nine hundred and ninety-nine

99,999,999,999 ninety-nine billon, nine hundred and ninety-nine million, nine hundred and ninety-nine thousand, nine hundred and ninety-nine

999,999,999,999 nine hundred and ninety-nine billon, nine hundred and ninety-nine million, nine hundred and ninety-nine thousand, nine hundred and ninety-nine