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## Main Question or Discussion Point

Submitted by @PeroK

Consider all 7-digit numbers which are a permutation of the digits 1-7. How many of these are divisible by 7?

Can you prove the answer algebraically, rather than simply counting them?

Please make use of the spoiler tag

Consider all 7-digit numbers which are a permutation of the digits 1-7. How many of these are divisible by 7?

Can you prove the answer algebraically, rather than simply counting them?

Please make use of the spoiler tag