Calculation: (+ 1) + (- 2) + (+ 3) + (- 4) + +(+99)+(-100)
(+1)+(-2)+(+3)+(-4)+… +(+99)+(-100),=[(+1)+(-2)]+[(+3)+(-4)]+… +[(+99)+(-100)],=(-1)+(-1)+… +(- 1), (50) = - 50
RELATED INFORMATIONS
- 1. (1+2+ 3+•••+99+100)×12345=?
- 2. 1 points 2 + 2 points 2 + 3 points 2 + &_; &; &; 99 points 2 + 100 points 2=
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- 7. If n is a positive integer and X2N = 7, then the value of (3x3n) 2-4 (x2) 2n is () A. 833B. 1225C. 2891D. 3283
- 8. Super difficult math problems in Volume 2 of junior high school Given m ^ 2 + 2m-1 = 0, find one of m ^ 2 + m ^ 2
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- 11. 1 times 2, 2 times 3, 3 times 4.99 times 100. Calculate the sum of the reciprocal of the first 99 terms
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- 13. Find the reciprocal sum of 1 * 2,2 * 3,3 * 4.99 * 100
- 14. 11×12+12+13×14+.+99×100,
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- 17. It's better to have a formula and why, 3Q 1. There are eight numbers in a row. If the average number of the fifth number on the left is 36, and the average number of the fifth number on the right is 34, and the average number of these eight numbers is 32, then what is the average number of the middle two numbers? 2. The average number of the three numbers of a, B and C is 150, the number of a is 48, the number of C is the same as that of B, and the number of B? 3, In order to make the average score of the four games 145, how many points should she get in the fourth game? 4. The average of the five numbers is 11. After changing one of the five numbers to 3, the average of the five numbers is 8. What is the original number? 5. Li Na, Wang Lei and Zhang Rui bought 10 loaves of bread. They shared the bread on average. Li Na took out the money for six loaves and Wang Lei took out the money for two loaves, Zhang Rui doesn't have any money with him. After eating, Zhang Rui should take out 1.25 yuan and ask Li Na how much yuan she should take back. 6. The average score of a class is 85.13 points according to the statistics of Chinese test results. The review found that Wang Lu's 87 points are wrongly written as 78 points. After recalculation, the average score of the class is 85.31 points. How many students are there in the class?
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- 20. The purchase rule of a commodity is: no more than 100 pieces, according to B yuan per piece; if more than 100 pieces, according to (b-20) yuan per piece. It costs a yuan to purchase no more than 100 pieces now. If 13 pieces are added on this basis, the cost is still a yuan. If the purchase price is set to be whole yuan per piece, then B yuan=______ .