Ответ:

2, 3, 6:

2 · 3 = 6
3 · 2 = 6
6 : 2 = 3
6 : 3 = 2

2, 6, 12:

2 · 6 = 12
6 · 2 = 12
12 : 2 = 6
12 : 6 = 2

2, 5, 10:

2 · 5 = 10
5 · 2 = 10
10 : 2 = 5
10 : 5 = 2