First, the first method is drawing, and the answer is shown in the figure.
The second method: Let the number whose distance on the number axis is-1 equal to 2 be X.
IX-(- 1)I=2
X+ 1=2 and X+ 1=-2(I? I is the sign of absolute value, and both positive and negative absolute values are equal to positive numbers, such as I- 1I= 1, I 1I= 1.
The solutions are X= 1 and X=-3. ? The answers are "1" and "-3".
2. 1. Total number of people: the total number of people who have met the conditions "e has 3033 people (41.5%)" = 3033/41.5% = 7309 people.
2. Number of people in D: 7309 * 12.2%=892, so there are 7309-1995-965-892-3033 = 424 (people) in Part A.
Therefore, A accounts for 424/7309 = 5.8%, and B accounts for 1995/7309 = 27.3%.
Third, from the title, we can know the increasing arrangement of each line with "1" as the variance (I don't remember whether it is called variance, then you can ask the teacher or find a book and do it now). The variance of each column is "8".
(1) If the middle number in the box is X, the middle number in the first row in the box is X-8. (The first number in the first line is X-8- 1, which means X-9, and the third number in the first line is X-8+ 1, which means X-7).
The number in the lower right corner of the box is X+8+ 1, which is X+9 (the first number in the third row is X+7, the middle number is X+8, and the third number is X+9).
(2) Write a simple idea according to the first small question.
Jean: the number in the middle is X.
9*X=2700? Get X=300. The smallest number is X-9, so it is 300-9=29 1, and the largest number is X+9=309.
Note: X is the median of these 9 numbers, which is also the law of median. The following is the proof: (x-9)+(x-8)+(x-7)+(x-1)+x+(x+1)+(x+7)+(x+8)+(x+9) = 277.
(3) It is also assumed that the middle number is X. ..
9*X=5400 X=600? The maximum quantity is 609.