This cannot be answered because the common multiples of any two or more numbers are infinite.
There is no highest common multiple of 56, 98 and 168. Their highest common factor, which you may have meant, is 14.
The Least Common Multiple (LCM) for 28 21 56 is 168.
The least common multiple of 3, 21, and 56 is 168.
The least common multiple (LCM) of 21, 56, and 63 is 504.
The greatest common multiple of any set of integers is infinite.
LCM(21, 42, 56) = 168.
The greatest, (Highest) Common Factor of 21 and 56 is 7
The GCF of 35 and 56 is 7.The LCM of 35 and 56 is 280.
840
The least common multiple of 14 and 21 is 42.14, 28, 42, 56 ...21, 42, 63, 84, ...
The least common multiple (LCM) of 18, 21, and 56 is 504.
The highest common factor is 7