Why is the lcm of two numbers never less than the larger number?
1 answer:
This involves a bit of logic in thinking about what LCM actually means.
LCM is the least common multiple. A common multiple is a multiple shared by two or more numbers. And by multiple, we mean some number multiplied by successive integers; this set contains multiples of 5 {5, 10, 15, 20, 25...}. You can see that the least (or lowest) common multiple is the lowest multiple shared by two numbers. Like for 6 and 9, you have {6, 12, 18, 24...} and {9, 18...}, so LCM(6,9) = 18.
Now, if an LCM must be shared by both numbers, and to get a multiple of the largest number, you have to multiply by an integer greater than or equal to 1, then the LCM of two numbers can never be less than the larger of the twi numbers. Generally, if x and y are positive real numbers, and x is greater than y,
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LCM is the least common multiple. A common multiple is a multiple shared by two or more numbers. And by multiple, we mean some number multiplied by successive integers; this set contains multiples of 5 {5, 10, 15, 20, 25...}. You can see that the least (or lowest) common multiple is the lowest multiple shared by two numbers. Like for 6 and 9, you have {6, 12, 18, 24...} and {9, 18...}, so LCM(6,9) = 18.
Now, if an LCM must be shared by both numbers, and to get a multiple of the largest number, you have to multiply by an integer greater than or equal to 1, then the LCM of two numbers can never be less than the larger of the twi numbers. Generally, if x and y are positive real numbers, and x is greater than y,
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