7. If a natural number can be written as the sum of two consecutive natural numbers and also as the sum of three consecutive natural numbers, it is called a "good number." Please find the "good number" among 2007, 2008, 2009, 2010, 1011.
7. If a natural number can be written as the sum of two consecutive natural numbers and also as the sum of three consecutive natural numbers, it becomes a "good number". Please find the "good number" among 2007, 2008, 2009, 2010, 1011.
【Analysis】Two consecutive natural numbers must be one even and one odd, their sum must be an odd number, so we first eliminate the even numbers; the sum of three consecutive natural numbers must be a multiple of 3, and according to the characteristics of multiples of 3, the sum of the digits must be a multiple of 3, find the odd numbers that are multiples of 3, which will be the good numbers.
【Solution】Solution: The sum of two consecutive natural numbers is definitely an odd number,
so 2008, 2010 are definitely not good numbers;
For 2007, $2+0+0+7=9, 9$ is a multiple of 3, so 2007 is a multiple of 3, it can be expressed as the sum of three consecutive natural numbers, it is a good number;
i.e., $2007=1003+1004=668+669+670$;
For 2009, $2+0+0+9=11$ is not a multiple of 3, so 2009 is not a multiple of 3, it is not a good number;
For 1011, $1+0+1+1=3, 3$ is a multiple of 3, so 1011 is a multiple of 3, it is a good number,
i.e., $1011=505+506=336+337+338$.
Answer: The good numbers among these are 2007, 1011.