Find the common difference of the arithmetic sequence.2, 1 8/9, 1 7/9,1 2/3, . . a.9b.-1/9c.-9d.1/9

For this case we have the following arithmetic sequence:
 2, 1 8/9, 1 7 / 9,1 2/3,. . .
 The common difference is given by the difference between two consecutive terms of the series.
 Therefore, for this case we have:
 
 Rewriting:
 
 
 
 
 
 
 The common difference of the arithmetic sequence is:
 b.-1/9