1 and 2
Since 36 is a factor of 72, all of its factors are common and all less than 200. Common multiples in that range are 72 and 144.
Multiples of 50 that are less than 200 are 100 and 150.
3. All other multiples of 3 are not prime.
250, 300, 350, 400, 450.
6
... 7 x 30 = 210, that should give you a clue...
42 and its next three multiples.
Multiples of 100 include 100, 200, 300, 400 and so on. For them to be common, they need to be compared to another set of multiples.
100, 200, 300, 400, 500, 600, 700, 800, 900
The Least Common Multiple (LCM) for 200 18 is 1,800
The LCM is: 600
108, 120, 132, 144, 156, 168, 180, 192