Express the following recurring decimals into vulgar fractions :

(a) = 0.666….      .........(1)
10 ×   = 6.666…    ........ (2)
   (2) - (1) 𡴩 ×  = 6
∴   = 6/9 = 2/3  
(b) = 0.161616….. ---(1)
100 ×   = 16.1616….. -----(2) 
Subtracting (1) from (2) , we get 
    99 ´   = 16
∴   = 16/99  
(c) 0.  = 0.234234….. ----(i)
1000 × 0. = 234.234234… -----(ii) 
Subtracting (i) from (ii) , we get
999 × 0.  = 234
∴ 0.  = 234/999.  
(d)   = 0.125454….                  -----(i)
∴ 100 ×   = 12.545454….        -----(ii)
And, 10000 ´   = 1254.5454… -----(iii)
Subtracting (ii) from (iii) , we get 
9900 ×   = 1242 
∴  = 1242/9900 = 69/550.