1) 12

48 = 2 * 2 * 2 * 2 * 3

84 = 2 * 2 * 3 * 7

2) 3

135 = 3 * 3 * 3 * 5

384 = 2 * 2 * 2 * 2 * 2 * 2 * 2 * 3

3) 60

180 = 2 * 2 * 3 * 3 * 5

840 = 2 * 2 * 2 * 3 * 5 * 7

4) 20

60 = 2 * 2 * 3 * 5

100 = 2 * 2 * 5 * 5

5) 1

6 = 2 * 3

23 = 23

6) 15

105 = 3 * 5 * 7

720 = 2 * 2 * 2 * 2 * 3 * 3 * 5

7) 6

36 = 2 * 2 * 3 * 3

42 = 2 * 3 * 7

84 = 2 * 2 * 3 * 7

8) 15

75 = 3 * 5 * 5

90 = 2 * 3 * 3 * 5

120 = 2 * 2 * 2 * 3 * 5