Arrange the natural number 1 23 4 5 6 7 8 9 in turn and write it down repeatedly to form a 1999 digit. Can this number be divided by 9? Why? It's best to have specific instructions

Arrange the natural number 1 23 4 5 6 7 8 9 in turn and write it down repeatedly to form a 1999 digit. Can this number be divided by 9? Why? It's best to have specific instructions


You don't have an ellipsis either. Do you want to use these 9 numbers to repeat the permutation, or use the following numbers to continue the permutation? 1) if you use these 9 numbers to repeat the permutation, the final permutation is 1234.7891. The sum of these numbers is (1 + 2 +.. + 9) * 222 + 1 = 9991, so the 1999 digit can't be divided by 9