It is infinity but the lowest is 63
The highest common multiple of any set of integers is infinite.
630 is the result of 5*9*7*2 and is also the least common multiple.
63 is the smallest multiple of 7 and 9
The highest common multiple is an infinite number.
There is no such thing as a highest common multiple of numbers, as numbers continue on forever. Note the difference between a Lowest Common Multiple (LCM) and a Highest Common Factor (HCF). The Lowest Common Multiple of 9, 7, and 5 is 315.
First work out the lowest common multiple of 7, 8 and 9 and then any multiple of this is a common multiple of 7, 8 and 9. The method I use is to list the numbers in their prime factorisation in power format; then the lcm is the product of each prime used to the highest power with which is appears in any of the factorisations. For 7, 8 and 9 this gives: 7 = 7 8 = 2^3 9 = 3^2 lcm = 2^3 x 3^2 x 7 = 504
The Least Common Multiple of 7, 9: 63
The smallest multiply of 7 divisible by 9 is the lowest common multiple of 7 and 9: lcm(7, 9) = 63.
The least common multiple of 7, 9 and 12 is: 252
The LCM of 2, 9, and 14 is 126, which is the multiple of the highest power of prime factors in the given numbers (2 x 3^2 x 7).
The set (35,7) has an LCM of 35 and a GCF of 7. The highest common multiple doesn't exist. Numbers don't stop.
The highest common multiple is an infinite number and not very practical for everyday use.