Write the remainder obtained when 1! + 2! + 3! + ...+ 200! is divided by 14.

We can see, from 7! onwards the terms are divisible by 14.


7!=7×6×5×4×3×2×1


=(7×2)×6×5×4×3


=14×360


So, we should consider up to 6! term to obtain the remainder.


Now,


1! + 2! + 3! + 4! + 5! + 6!


= 1 + 2 + 6 + 24 + 120 + 720


= 873


On dividing 873 by 14, we get 5 as remainder.


14×62=868


and 873-868=5


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