Summary rule: 1 / N (n + 1)=________ Using this law, we can calculate: half + one sixth + one twelfth + one twentieth + one thirtieth

1/n(n+1)=1/n-1/(n+1)
Original formula = 1 / 1 × 2 + 1 / 2 × 3 + 1 / 3 × 4 + 1 / 4 × 5 + 1 / 5 × 6
=1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6
=1-1/6
=5/6

RELATED INFORMATIONS

1. From 11 × 2 = 12, 11-12 = 12; 12 × 3 = 16, 12-13 = 16; 13 × 4 = 112, 13-14 = 112 The conclusion is: 1n (n + 1)=______ Using this law, we can know that 11 × 2 + 12 × 3 + +1n(n+1)=______ ．
2. 1, - 2,3, - 4?
3. The following group of numbers are written according to a certain rule: - 1,2, - 3,4, - 5 ·······, then what is the nth number
4. Find the rule: 1-1 -, 2-2,3-4,4-8,5-16 find the nth number
5. The law of 1 * 2 * 3 * 4 * 5 * 6 * ····· n
6. -The law of 1 2 - 3 4 - 5 6 is expressed by n
7. Find the rule: 1 / 2, 1 and 2 / 3, 2 and 3 / 4, (), 4 and 5 / 6, ()
8. How much is it from 1 to 100?
9. What's 1 up to 100
10. From 1 to 100, what is the result?
11. (1 + 1) × 1 / 2 = 1, (1 + 1) × 2 / 2, (1 + 3) × 3 / 2, (1 + 4) × 4 / 2?
12. -1 * (1 / 2) = - 1 + (1 / 2), - (1 / 2) + (1 / 3) = - (1 / 2) + (1 / 3), - (1 / 3) * (1 / 4) = - (1 / 3) + (1 / 4) (1) Rule: () is expressed by a formula containing N, where n is a positive integer (2) Use the above rule to calculate: (- 1 * (1 / 2)) + (- (1 / 2) * (1 / 3)) + (- (1 / 3) * (1 / 4)) +. + (- (1 / 2012) * (1 / 2013)) ask for the answer!
13. What is the law of 1 + 2 = 3 and 4 + 3 + 2 + 1 + 1?
14. What's the rule of 2 / 3,1,3 / 2,9 / 4
15. 1/3+1/6+1/12+1/24+…… +1/3*2^n-1+…… = ditto
16. Fill in the number according to the law. (1 point) & nbsp; & nbsp; 1, 3, 2, 6, 4______ ，______ ，12，16，…
17. 1/2=1/1*2=1/1-1/2,1/6=1/2*3=1/2-1/3,1/12=1/3*4=1/3-1/4. Calculate 1 / (X-2) (x-3) - 2 / (x-1) (x-3) + 1 / (x-1) (X-2)
18. 1, 3, 2, 6, 4, (), (), 12 ()·····
19. What's the fastest formula from 1 10 2 10 3 to 100
20. How much is it from 1 to 100? What's the formula?