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Number game: the first line 28 7 7 6, the second line 9 9 8 8, the third line () 5 13 16, 5 B, 17 C, 19 D, 47 which one Let's talk about the reasoning process
28 7 7 6
9 9 8 8
5 13 16
5+9=14/7=2
13+8=21/7=3
16+8=24/6=4
So x + 9 = Y / 28 = 1, y = 28-9 = 19 = x, so choose C
The odd numbers 1,3,5 In this way, the n-th group has n numbers, i.e. (1), (3,5), (7,9,11), (13,15,17,19)
So which group is 2013 in? Which number is this group
The nth group is n numbers from n ^ 2-N + 1 to n ^ 2 + n-1
Group 45, from 1981 to 2069, 2013 is the 17th
Let 1, - 2,3, - 4,5, - 6 According to a certain rule, the order is as follows: 1 - 23 - 45 - 67 - 89 - 1011 - 1213 - 1415 - 16
Let 1, - 2,3, - 4,5, - 6 According to a certain rule, they are arranged as follows: 1
-2 3 -4
5 -6 7 -8 9
-10 11 -12 13 -14 15 -16
The ninth number from left to right in line 10 is? The answer is - 90,
The mantissa of the first line is 1, that is 1 & # 178;
The mantissa of the second line is - 4, that is - 2 & # 178;
The mantissa of the third line is 9, that is, 3 & # 178;
The mantissa of the fourth line is - 16, that is - 4 & # 178;
So the last number in line 9 is: 9 & # 178; = 81
So the ninth number in line 10 is: 81 + 9 = 90
Because even numbers are - 90
The natural numbers are grouped according to the following rules: (1), (2,3,4), (5,6,7,8,9)... In which the first group has one number and the second group has three numbers
The third group has five numbers. What is the sum of all the numbers in the eighth group
Observe the law
The eighth group has 2 * 8-1 = 15 numbers
Before the eighth group, there are 7 ^ 2 = 49 numbers
So the eighth group is an arithmetic sequence with 50 as the first term, 1 as the tolerance and 15 as the number of terms
So the sum of all numbers in the eighth group is 50 * 15 + 15 * 14 / 2 = 750 + 105 = 855
RELATED INFORMATIONS
- 1. Observe the following table 1 2 3 4 The first line 2 3 4 5 The second line 3 4 5 6 The third line 4 5 6 7 The fourth line The first, second, third and fourth columns guess that the number at the intersection of the sixth row and the sixth column should be______ , the number at the intersection of row N and column n should be______ (expressed by a formula containing a positive integer n)
- 2. A math problem. 1.2.7.14.23.34. How to find the law
- 3. Look at the following table ~ and answer what numbers x ~ and y are 0 1 1 1 0 0 1 2 2 5 5 x 2 0 0 5 y 14 16 16
- 4. If a number is a multiple of 2 and 3, it must be a multiple of 6______ ．
- 5. There are 10 red, yellow, blue and white balls, which are mixed and put in a cassette. At least how many balls must be found at a time to ensure that there are 6 balls in the same color
- 6. There are 10 red, yellow, blue and white balls each, mixed in a cassette, and at least one touch out______ In order to ensure that there are six balls in the same color
- 7. There are ten small balls in red, yellow, blue and white. Put them in a cloth bag and find five at a time. How many of them have the same color? 9, 13. What's the rule
- 8. There are 10 red, yellow and blue balls in your pocket. Close your eyes and make sure you can touch many four balls of the same color at a time. How many can you touch What's the formula
- 9. In a box, there are 20 balls of red, yellow, blue, green and white. At least touch a few balls to ensure that there are two balls of each color? Come on the sooner the better Within an hour
- 10. If four different balls are put into four red, yellow, blue and green boxes, there is exactly one empty box
- 11. It is necessary to arrange 2 / 3, 5 / 6, 5 / 13 and 11 / 18 in descending order
- 12. Take 6 / 11, 10 / 17, 15 / 26, 5 / 8, 12 / 19 from small to large, which score is at the top
- 13. The numbers 1, - 1 / 2,1 / 3, - 1 / 4,1 / 5, - 1 / 6 are arranged as follows according to certain rules, First line 1 Second line - 1 / 2 1 / 3 The third line - 1 / 4 1 / 5 - 1 / 6 The fourth line 1 / 7 - 1 / 8 1 / 9 - 1 / 10 The fifth line 1 / 11 - 1 / 12 1 / 12 - 1 / 14 1 / 15 ………… ……………… ………… So, can you write 10 numbers from left to right in line 20?
- 14. Use 2, 1, 6 and 8 to form different three digit numbers, and arrange them in the order from small to large
- 15. Some three digit numbers are divided by 3.5.7 to make up 2. Arrange these three digit numbers from small to large, and the fourth number is
- 16. Numerical reasoning - 1,0,1,8, (), 64 what should be filled in brackets
- 17. What do you fill in the brackets? Why
- 18. Number reasoning: 227238251259,)
- 19. Number reasoning: 1, 2, 3, 7, 16, (), the number in brackets should be? A.58 B.62 C.65 D.68
- 20. The first number in the nth row is () and the nth row has () numbers one 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 . one 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 ......................