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刚刚在别的gmat讨论版上看到的 搬过来~: 0 is a multiple of every number and a factor of no number.
Many questions specifically reference "positive multiples", but if they don't then negative numbers can also be multiples.
For example, the set of all multiples of 5 is:
{... -15, -10, -5, 0, 5, 10, 15, ...}
By convention, if a question asks for the lowest common multiple of two numbers, the answer will be the lowest common positive multiple.
回答问题的这个人好像蛮厉害的, 还写过gmat. 应该是正确的了吧。经供参考。 哎。。 好烦啊。。。 |