1/1*2*3+1/2*3*4+.+1/20*21*22

1/1*2*3+1/2*3*4+.+1/20*21*22

1/1*2*3=(1/1*2-1/2*3)*1/21/2*3*4=(1/2*3-1/3*4)*1/2…… 1/20*21*22=(1/20*21-1/21*22)*1/2 1/（1*2*3）+1/（2*3*4）+1/（3*4*5）+...+1/（20*21*22）=(1/1*2-1/2*3)*1/2+(1/2*3-1/3*4)*1/2+.+(1/20*21-1/21*22)*1...

1/1*2*3+1/2*3*4+1/3*4*5+…… +20*21*22=?

Look at the picture

1 /1*2*3+1/2*3*4+1/3*4*5+.+1/20*21*22=?

1/1*2*3=(1/1*2-1/2*3)*1/21/2*3*4=(1/2*3-1/3*4)*1/2…… 1/20*21*22=(1/20*21-1/21*22)*1/2 1/（1*2*3）+1/（2*3*4）+1/（3*4*5）+...+1/（20*21*22）=(1/1*2-1/2*3)*1/2+(1/2*3-1/3*4)*1/2+.+(1/20*21-1/21*22)*1/...

How to fill in 456789101112 numbers in the nine palace grid, add them horizontally, vertically and obliquely, and the sum equals 24

11 6 7
4 8 12
9 10 5

How to fill in 0123456789 numbers in the nine palace grid, add them horizontally, vertically and obliquely, and the sum is equal to 12

507
six hundred and forty-two
one hundred and eighty-three

Put these nine numbers into the circle, so that the sum of the three numbers on each line is equal. The circle is arranged in four directions

26 21 28
27 25 23
22 29 24

21 22 23 24 25 26 27 28 29 how to put these nine numbers so that they are added horizontally, vertically and obliquely, and the result is 75
21 22 23
24 25 26
27 28 29
How to put these nine numbers so that they can be added horizontally, vertically and obliquely to get 75

26 21 28
27 25 23
22 29 24

Add the nine numbers 21-29 to the grid so that each row and column is 75
o o o
o o o
o o o

22 29 24
27 25 23
26 21 28
Simple, there are ways to follow

The horizontal, vertical and oblique of Jiugong grid are all equal to 75, and only the numbers 21 to 29 can be used

24 23 28
29 25 21
22 27 26

Fill 21-29 in the nine square. Make the sum of horizontal, vertical and oblique equal to 75

22 29 27
27 25 23
26 21 28