That is, given six numbers and a target number,
find an arithmetical expression containing exactly those six numbers
that yields the target number.
The solver however is neither limited to a certain number of operands
nor to a certain magnitude of numbers
nor to uniqueness of the operands.
Please note, that the solver also emits solutions
where not all of the given operands are used.
The solver employs a brute-force search,
but ensures that expressions are unique up to commutativity and associativity.
It determines all solutions of a problem within seconds.
