Solution: According to the meaning of the question, the difference between the two groups is 20 13, that is, from 1 to 20 12, the difference is 0.

Because the number 20 12 can be divided into two groups, and each group is 20 12/2= 1006.

The result of adding the first and second digits is 2012+1= 2013. If the first and second digits are removed, the remaining first and second digits are 2+2011= 2013.

By analogy, the sum of 20 13 can be divided into 1006 groups, and then 1006 groups can be divided into two groups with 503 in each group.

The difference between the two groups is only 0.

So this problem can divide the singular numbers into one group (1.3.5.7 ... 201.2013).

Even numbers are divided into a group 2.4.6.8...20 12)

That is, it fits the meaning of the question.