The LCM of these numbers is 137235. LCM is Least Common Multiple.
The LCM of 1,240 and 3,921 is: 4,862,040
The LCM of 3 and 9 is 9.
2475
7 can divide into the LCM of some sets of numbers, not others.
20 and 30 among others
20 and 30, for one.
There are many possible sets. (1, 60) is one such.
20 and 30 4 and 15
You cannot. The numbers 2 and 12 have hcf = 2 and LCM = 12 The numbers 4 and 6 also have hcf = 2 and LCM = 12 So if you just knew the hcf and LCM you would not know which of the two was the required pair.
Zero creates some funny situations and is best avoided. Other than that, all sets of numbers have an LCM and at least one common factor.
The LCM of 22, 55 and 77 is 770. The LCM of 24, 35 and 49 is 5880. The LCM of 8, 44 and 105 is 9240. The LCM of 225, 245 and 280 is 88200.