3\51+4\51+6\51+...+58\51-1\51-3\51-5\51-...49\51

3\51+4\51+6\51+...+58\51-1\51-3\51-5\51-...49\51

The first 3 in 3 / 51 + 4 / 51 + 6 / 51 +... + 58 / 51-1 / 51-3 / 51-5 / 51 -... 49 / 51 should be 2.58 and should be 50, that is, 2 / 51 + 4 / 51 + 6 / 51 +... + 50 / 51-1 / 51-3 / 51-5 / 51 -... 49 / 51 = (2 / 51-1 / 51) + (4 / 51-3 / 51) -- + (50 / 51-49 / 51) = 1 / 51 + 1 / 51 - + 1 / 51 (25 in total) = 25 / 51