The question is quite "simple". Let $\lambda$ denote the usual Lebesgue measure on $\mathbb R.$ Let $E\subseteq [0,1]$ be a non-measurable subset. Do we **always** have
$$
\lambda(E) +\lambda ([0,1]\backslash E) >1?
$$
Are there examples of non-measurable sets such that equality $\lambda(E) +\lambda ([0,1]\backslash E) =1$ holds?

Although this is very easy to state, it is very hard to think of what examples do we have. After all, the construction of a non-measurable set along is not that easy. The Vitali set does not provide the example asked for above.