\(a-68=\left(3\frac{10}{11}-4\right):\left(\frac{2121}{2222}-1\right):\left(\frac{33333}{343434}-1\right)\)
\(a-68=\left(\frac{43}{11}-4\right):\left(\frac{-1}{22}\right):\left(\frac{-310101}{343434}\right)\)
\(a-68=\frac{-1}{11}.\frac{-22}{1}.\frac{-343434}{310101}\)
\(a-68=\frac{1}{11}.\frac{22}{1}.\frac{343434}{310101}.\left(-1\right)\)
\(a-68=\frac{-686868}{310101}\)
\(a=\frac{-686868}{310101}+68\)
\(a=\frac{-20400000}{310101}\)
Vậy \(a=\frac{-20400000}{310101}\)