You have to have two different numbers to find common multiples
The least common multiple of 140 and 148 is 5,180
The least common multiple of 7 and 20 is 140. The next 4 common multiples come from 140 x 2, 140 x 3 etc...
Common multiples of 14 and 35 include 70, 140 and 210
Common multiples of 14 and 20 include 140, 280 and 420
140
140
Common multiples of 7 and 5 include 35, 70, 140, etc.
70, 140, 210
The LCM of 7 and 20 is 140
70 and 140
140, 280, 420 and so on.