15 and 30
They are: 30 and 60
30 and 60
A single number cannot have common multiples, until you are comparing it with one or more other numbers.
The two common multiples of three and five are: 15 and 30 ^-^
Since 3 and 5 are both prime numbers, the only common factor of the two numbers is 1. Perhaps you are thinking of common multiples, the first two common multiples of the two numbers are 15 and 30.
30, 60, 90, 120, 150
The common multiples of 5 and 6 are the multiples of their lowest common multiple (which is 30), so there are infinitely many common multiples of 5 and 6. The first five are: 30, 60, 90, 120, 150.
To find the common multiples of 16 and 30, first find the LCM: The prime factorization of 16 is 2*2*2*2 The prime factorization of 30 is 2*3*5 So the LCM is 16*30 / 2 = 240. All of the common multiples of 16 and 30 will be multiples of 240, so they are 240, 480, 720, 960, 1200, etc. There is an infinite number of common multiples for 16 and 30. A common multiple of any two numbers is any number into which each of two or more numbers can be divided evenly (zero remainder).
10, 20, 30 The common multiples of 5 and 10 are multiples of their lowest common multiple. The lcm of 5 and 10, is 10. Thus the first three common multiples are 10, 20, 30.
The first five multiples of 6 are 6, 12, 18, 24 and 30. For them to be common, they need to be compared to another set of multiples.
The first three multiples of 235 are 235, 470 and 705. For them to be common, they need to be compared to another set of multiples. The first three common multiples of 2, 3 and 5 are 30, 60 and 90.