Connect 1.2.3... 30 and make it a 51 digit number. How much is it divided by 9? How much is it divided by 11?

Connect 1.2.3... 30 and make it a 51 digit number. How much is it divided by 9? How much is it divided by 11?

Divided by 9 and 6, it's 123456 27 can be divided by 9, so 282930 / 9 leaves 6; and dividing by 11 is troublesome. You need to find the number that can be divided by 11 first, and then divide by 11 with the following number. I won't count. The characteristics of numbers that can be divided by 11 are as follows: starting from the right, the sum of odd numbers - the sum of even numbers is a multiple of 11 or 0

Use the 9 numbers 1 ~ 9 to form a 2000 digit 123456789 123456789
How many digits is this 2000 divided by 9?

Because every number of nine is a multiple of nine, for example, 123456789 million, and 123456789 million, are all the same
So just look at the last few, 2000 / 9 over 2, that is, the last two are 12
12 / 9 = 1 surplus 3
So the remaining three

The natural number 102030405060708090 is a 17 digit number. The remainder of this 17 digit number divided by 175 is

The natural number 102030405060708090 is a 17 digit number. The remainder of this 17 digit number divided by 175 is
fifteen

There are seven numbers from small to large, and the average is 38. The average of the four numbers in this group is 33, and the average of the last four numbers is 42, and the median is 33

Let the median be X
4*33 4*42=7*38 x
The solution is x = 34
perhaps
33×4 42×4-7×38=34
Our teacher said (^_ ^)