Which sets does the number negative sixteen belong to?

Answer 1

To any set that contains it!

It belongs to {-16},

or {-16, sqrt(2), pi, -3/7},

or all whole numbers between -43 and 53,

or the square roots of 256,

or multiples of 4,

or negative numbers,

or integers,

or rational numbers,

or real numbers,

or complex numbers,

etc.