one 2 3 4 5 6 7 8 9 10 11 12 13 14 15 …………………………………… What line should 2005 be on? What number from left to right on this line Calculate 1 + 1 / (1 + 2) + 1 / (1 + 2 + 3) + 1/(1+2+3… ＋2005）

45 lines on the line from left to right the 69th number 1 + 2 + 3 ＋n=n(n+1)/2 1＋1/(1+2)+1/(1+2+3)+… 1/(1+2+3… ＋2005）=1+2/2*3+2/3*4 +2/2005*2006=1+2(1/2-1/3+1/3-1/4+1/2005-1/2006) =1+2(1/2-1/2006) =2-1/2003

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1. Several mathematical problems for finding laws will be solved today 1. Observe the following equation: 9-1=8 16-4=12 25-9=16 36-16=20 …… Let n (n is greater than or equal to 1) denote a natural number. Let n denote the law as () 2. Xiaohong from a to B, at the speed of 2 meters per minute, she first forward 1 meter, then backward 2 meters, then forward 3 meters, then backward 4 meters According to this rule, one hour later, she is () meters away from the ground 3. The two electric toy cars a and B run from both ends of the track at the same time. Car a runs 5 cm per second, car B runs 1 cm in the first second, 2 cm in the second second, and 3 cm in the third In this way, when the two cars meet, they travel the same distance. Then the track length is () cm 4. The surface area of the first figure is 6 square units, the surface area of the second figure is 18 square units, and the surface area of the third figure is 36 square units. According to this rule, the surface area of the fifth figure is () square units
2. 77 （） 36 18 8
3. 1,8,18,32, () solve the numbers in brackets What's the next number
4. Four numbers 3, 6, 9 and 12 form a formula with addition, subtraction, multiplication, division sign and brackets, and the result is 24 At least 3
5. Add numbers in brackets to form words () flowers in full bloom Think and act () () unification
6. What does the number in the last bracket of 6 + 1 mean? For example, buy bet 6 + 1 It's 8 15 14 9 5 17 - 3 (01) That (01) and that - 3
7. Tennis match score "6-3 7-6 (4)"
8. 5 / 6 △ () > 5 / 6 find the number in brackets
9. What are the numbers in brackets Fill in the numbers regularly, why
10. () 0 () × () 6 = () () 58 (), what are the numbers in brackets
11. （1）、 3、 4、 7、 9、 11、 14、（15）（19）（2）、 196、 148、 108、 76、（52）（36）（3）、 1、 2、 4、 4、 9、 8、 16、 16、（25）（32）
12. Finding the law in the first day of junior high school Don't be too simple·
13. 0,3,8,15,24, (), (), ()... The number 2003 is
14. What is the number 2002 of 0,3,8,15,24
15. Observe the law of the following column and fill in the blanks: 0, 3, 8, 15, 24 Then its number 2002 is______ ．
16. Observe the law of the following column and fill in the blanks: 0, 3, 8, 15, 24 Then its number 2002 is______ ．
17. What's the 36th number in math problem 5 7 9 11 down 3 8 15 24 35 up 3 8 15 24 35 ————————Find out the law of up and down, and calculate the number of the 36th digit with the fastest speed! 5 7 9 11
18. Arrange 3 numbers in turn (4) Use your conjecture to calculate the sum of all the numbers of the new number string generated after the 2010 operation? Subtract the number on the left from the number on the right, and write the difference between the two numbers to generate a new number string: 3,6,9, - 1,8, which is called the first operation. After the second operation, a new number string can be generated: 3,3,6,3,9, - 10, - 1,9,8. Continue to operate like this, and ask: (4) use your conjecture to calculate the sum of all numbers of the new number string generated after the 2010 operation?
19. 0,3,8,15,24… () (number 2010)
20. Find the rules and fill in the number questions 11, 12, 14, x, 26, 42 11,12,14,X,26,42 Excuse me x is what. Urgent. Cannot do. Sweat