Write in set builder form {all possible numbers formed by any two of the digits 1 2 5}

Write in set builder form {all possible numbers formed by any two of the digits 1 2 5}

With 3 numbers, we got 3! = 6 possible numbers formed by the two digits

1. 12
2. 15
3. 21
4. 25
5. 51
6. 52

In set builder notation, we write this as:
{x : x ∈ {12, 15, 21, 25, 51, 52})
x such that x is a element of the set {12, 15, 21, 25, 51, 52}