What subset does 0 5 13 25 30 35 45 belong to?

Answer 1

To any set that contains them!

They belong to {0, 5, 13, 25, 30, 35, 45},

or {0, 5, 13, 25, 30, 35, 45, sqrt(2), pi, -3/7},

or a selection of 7 integers between 0 and 45,

or counting numbers,

or integers,

or rational numbers,

or real numbers,

or complex numbers,

or the first six numbers in the sequence defined by Un = (-5n6 + 123n5 - 1181n4 + 5577n3 - 13394n2 + 15720n - 6840)/72

etc.