21, 28, 35, 42, 49
There are more than four, starting with 12, 15, 18 and 21.
You can multiply 7 by different integers.Or, once you have one multiple - in this case, 21 - you can repeatedly add 7 to get additional multiples. (Do a multiplication, now and then, as a check.)
The four multiples of seven are 7, 14, 21, and 28.
The first four multiples of 21: 21, 42, 63, 84
The number is infinite, starting with these: 462, 924, 1386, 1848 . . .
Their lowest common multiple is 63.
7, 14, 21, 28, 35, 42, 49
Multiples 21: 1,3,7,21Multiples 49: 1,7,49
LCM of 21 & 49 is 147, so all multiples of 147 are common multiples of 21 & 49.
The common multiples of 3 and 21 are 21, 42, 63 and so on.
The first 5 multiples of 21 are: 21, 42, 63, 84, and 105.
The first five multiples of 21 are: 21, 42, 63, 84, 105.