Melody

avatar
Имя пользователяMelody
Гол118725
Membership
Stats
Вопросов 900
ответы 33647

-4
850
3
avatar+118725 
Melody  11 февр. 2022 г.
 #1
avatar+118725 
+1

Well the answer is 2 but I do not know how to do it.

 

http://www.wolframalpha.com/input/?i=(sum+from+x%3D1+to+x%3D100+(x%5E3))+mod+7

 

I had done some other work (which i deleted) to decide that the last digit was 0.

I wonder if I can use that fact...

7,14,21,28,35,42,49,56,63,70  It seems multiples of 7 can end in any digit.  That doesn't seem very helpful.

 

I think there is some strange variation on the sum of GP that you can do this with but i have forgotten it...

14 мар. 2018 г.
 #1
avatar+118725 
0
14 мар. 2018 г.