abstract: The poster gives 3 examples in wich matching plays a role. There will be $\alpha$-continued fractions, Ito continued fractions and a subfamily of the $N$-expansions. In the first example all rationals will match. In the second there will be a distinction between good and bad rationals. In the third example we have no clue how to do matching. There will be an explanation why there is no 'easy argument' to conclude matching (for example 0 is not in the domain so it is not immediately clear why rationals should match).