MHB Divisibility of (1!+2!+3!+...+100!)^2 by 5

[stamenkovoca02]

1.The remainder when dividing (1!+2!+3!+...+100!)^2 by 5 is?
5 divides evenly into 5!, 6!, 7!, ..., 100!. It would also divide evenly into things like 2!*8! or 20!*83!, but not 4!*3!
but whether then ^2 affects the rest?
And what is answer?Thanks

 

[cbarker1]

You have to show some type of attempt. We can't provide the answer, but we can guide you to the answer.