Hi. It's one more hard task from cominatorics(adsbygoogle = window.adsbygoogle || []).push({});

We have 5 digit. How many 7-digit numbers can we create that each two of them have at least 2 different digit?

Could you help me?

I think that the answer is 5^6 but don't know how to prove it.

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# Homework Help: Combinatorics-next problem with numbers

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