1 times 4:1 plus 4 times 7:1 plus 7 times 10:1 plus... Plus 91 times 94:1

1 times 4:1 plus 4 times 7:1 plus 7 times 10:1 plus... Plus 91 times 94:1

1 x 1 / 4 = 1 / 3 (1 - 1 / 4) 1 / 4 x 1 / 7 = 1 / 3 (1 / 4 - 1 / 7)... According to this rule, the original formula can be changed into: 1 / 3 (1 - 1 / 4) + 1 / 3 (1 / 4 - 1 / 7) +... + 1 / 3 (1 / 91 - 1 / 94) = 1 / 3 (1 - 1 / 4 + 1 / 4 - 1 / 7 +... + 1 / 91 - 1 / 94) = 1 / 3 (1 - 1 / 94) = 31 / 94

Find a friend. (first line and second line) 17 / 4, 23 / 25, 113 / 25, 33 / 8 (first line)
0.92, 4.25, 4.125, 0.8, 0.904 (second line)

7 out of 4 for 4.25, 4 out of 5 for 0.8, 25, 23 out of 25 for 0.92125, 113 out of 8 for 0.904, 33 out of 8 for 4.125