Observe the following group of numbers in regular order: - 1,2, - 3,4, - 5,6, - 7,8... Then what is the number 2006?

Observe the following group of numbers in regular order: - 1,2, - 3,4, - 5,6, - 7,8... Then what is the number 2006?

:-1,2,-3,4,-5,6,-7,8.
Odd sign is negative, even sign is positive
The number of 2006 is 2006

Then fill in the blanks: 1, - 2,3, - 4.5, - 6.7, - 8.9__ , , ,

1,-2,3,-4.5,-6.7,-8.9,_ -10_ , 11_ , -12

Observe the following numbers: - 1,2, - 3,4, - 5,6, - 7 -1 2 -3 4 -5 6 -7 8 -9 10 -11 12 -13 14 -15 16 . In line 10, the ninth number from the left is___ . No. - 201 is No___ The rows are numbered from the left___ number

In the sequence above, the absolute value of the last number in each row is the square of the number of rows
The absolute value of the last number in line 9 is 9 ^ 2 = 81
So line 10 is {82, - 83,84. - 99100}
Line 10 is from the left and the ninth is 100
201=14^2+5
So - 201 is line 15 (14 + 1), the fifth number on the left

Observe the following column numbers: - 1,2, - 3,4, - 5,6, - 7 Arrange the numbers in the following order: -1 2 -3 4 -5 6 -7 8 -9 Follow this rule, and find the 10th line from the left to the 9th

There are 1 number in the first row (2 * 1-1), 3 numbers in the second row (2 * 2-1) The ninth row has 2 * 9-1 = 17 numbers, the first nine rows have (1 + 17) * 9 / 2 = 81 numbers, the 10th row has 2 * 10-1 = 19 numbers, the first number is 81 + 1 = 82, so the ninth number is 82 + 9-1 = 90

Put a column of numbers - 1,2, - 3,4, - 5,6, - 7,... Into the following form. What is the second number in the eighth row -1 2 -3 4 -5 6 -7 8 -9 10 -11 12 -13 14 -15 16 ... In this way, what's the second number from the left in line 8? How do you get it? Urgent use!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

There are 15 numbers in the eighth row of the sequence
In addition, the number in the next line is the increment of the first line (regardless of the sign). For example, there is a number in the first line. There are three numbers in the second line, which are 2, 3 and 4. So on, the last number in the seventh line is: 1 + 3 + 5 + 7 + 9 + 11 + 13 = 49, so the second number on the left of the eighth line is 49 + 2 = 51
Observe the sign again. The odd number of odd lines is negative, and the even number of even sign is negative
So the second number in line 8 is negative
To sum up, the final answer is - 51

There is a column of numbers arranged as follows: 5,6,7,8,5,6,7,8,5,6,7,8（ ）One

39 / 4 = 9 more than 3, so it's 7 and 5. There are 9

The number of a column in regular order: 2, - 4, 8, - 16, 32, - 64 The sum of the four adjacent numbers is - 640. What is the difference between the largest and the smallest of the four numbers?

Let the first of the four adjacent numbers be X,
Then the last three numbers are - 2x, 4x, - 8x
From the meaning of the title: x-2x + 4x-8x = - 640,
The solution is: x = 128
Then - 2x = - 256,
4x=512，
-8x=-1024．
∴512-（-1024）=1536．
That is, the difference between the largest and the smallest of the four numbers is 1536

No matter how many permutations there are, can you make a formula?

17 * 16 * 15 * 14 * 13 * 12 / 6 / 5 / 4 / 3 / 2 / 1 = answer

There are several cases of 1-12 numbers and 6 numbers arranged by size

In other words, 6 out of 12 can be selected. There are C (12) 6 924 selection methods. The selected numbers need to be from small to large or from large to small, so the total number is 924 * 2 = 1848

There are several possibilities for a combination of six numbers

6 ^ 6 = 26656 species