Compare the numbers by looking at the number of digits first.<br><br>&bull; 9908009 has 7 digits<br>&bull; 9080899 has 7 digits<br>&bull; 9088900 has 7 digits<br>&bull; 880990 has 6 digits<br><br>A 6-digit number is always smaller than any 7-digit number.<br><br>Final Answer: 880990