The factor of 15 is 1, 3,5, 15, and the factor of 12 is 1, 2,3,4,6, 12.
The factor of 42 is 1, 2,3,6,7, 14, 2 1, and the factor of 42,54 is 1, 2,3,6,9,18,27,54.
The factor of 30 is 1, 2,3,5,6, 10, and the factor of 1 5,30,45 is1,3,5,9,15,45.
The factor of 99 is 1, 3,9, 1 1, 33,99,36 is 1, 2,3,4,6,9, 12, 18.
The factor of 5 is 1, and the factor of 5 9 is 1, 3,9.
The factor of 34 is 1, 2, 17, 34, 17, and the factor is 1, 17.