Because the common multiples of any two or more numbers are infinite.
There is no "greatest common multiple" for any pair of numbers. If you meant greatest common factor, the answer is 3.
There is no greatest common multiple of these numbers... or indeed of any pair of numbers. Once you get a common multiple, you can multiply that by any integer, as large as you want, to get a larger common multiple.
Only if the magnitudes of two numbers are the same.
7 and 35
Since 70 is a multiple of 14, it is the least common multiple. Or, you can determine it as you would any pair of numbers. The least common multiple of two numbers is the product of the two numbers divided by their greatest common factor. The greatest common factor of 14 and 70 is 14. Therefore, the least common multiple 14 x 70 ÷ 14 = 70.
36 and 48 12 and any multiple of 12
There is no greatest common multiple of this or any pair of numbers. The least common multiple is 100 which is 5 times 20 and 2 time 50. However, 200,300,400, 500, 600, ..... are all common multiples as well.
6 and 9 are one pair of numbers with a common multiple of 18. Another pair are 9 and 18.
No.
48 and 36
A prime number