Two pairs of #'s with 10 as their least common multiple:
5x2
1x10
They are: 2 and 9, 1 and 18
21 and 35 7 and 15
5 and 21 15 and 7 35 and 3
(3, 36) and (4, 9)
The least common factor of any set of numbers is 1, so your problem won't work. 3, 5 and 10,15 have an LCM of 15. 15, 30 and 45,60 have a GCF of 15.
You need at least two numbers to find an LCM and there can only be one least common. If you want to know multiples of 105, just keep adding 105. 105, 210, 315 and so on.
1 and 1
The product of all pairs of prime numbers is always the least common multiple of the two prime numbers.
Select ALL pairs of numbers that have a least common multiple of 30
All pairs have the same same number of multiples: [countably] infinitely many.
12 and 18.12,24,36,48,60.18,36,54,72,90.
It means write down three pairs of numbers that are relatively prime like 4 and 9, 5 and 6, 13 and 25
Pick any two numbers. All pairs of numbers have an LCM.
There are many common multiples of 120 and 149. A common multiple is simply a multiple of both numbers. The least common multiple is 120x149, since 149 is prime. (Note: this trick doesn't work on all pairs of number. Although the product is always a multiple, it's not the least common multiple.)
20 and 25
2 and 5
(21,5)(15,7)