84
The highest common multiple of 21 and 84 is infinity. The least common multiple, on the other hand, is 84, while the greatest common divisor is 21.
The highest common multiple of any set of integers is infinite.
The greatest common multiple of any set of integers is infinite.
The common multiples of 21 and 28 are 84, 168, 252, 336, ... and so on, never ending; so there is no real Highest Common Multiple.Do you mean:Highest Common Factor - the highest number which divides both 21 and 28 which is 7; orLowest Common Multiple - the lowest number which is a multiple of both 21 and 28 which is 84.
3, as 3 can only go into 3 once and 21 seven times.
This cannot be answered because the common multiples of any two or more numbers are infinite.
The least common multiple of 21 , 19 = 399
The LCM of 10 and 21 is: 210Least Common Multiple (LCM) for 10 21 is 210
A common multiple of 9 and 21 is 63
The Least Common Multiple of 18 and 21 is 126.
The least common multiple of 6 , 21 = 42