+0  
 
0
98
4
avatar+33 

What are the last two digits in the sum of factorials of the first 100 positive integers?

 Jan 14, 2021
 #1
avatar+536 
0

13

Factorials greater than or equal to 10 ends in two zeros, which wont change the outcome

Add 1-9 factorials

1!+2!+3!+4!+5!+6!+7!+8!+9!=409113

 Jan 14, 2021
 #3
avatar+11 
0

those numbers get very big, very fast.

angelthecutehamster  Jan 14, 2021
 #4
avatar+33 
0

Ok! Thanks! I completely understand the problem now. Thanks!

guest.exe  Jan 14, 2021
 #2
avatar+11 
0

the last digit is the last digit of 1!+2!+3!+4!+5!+6!+7!+8!+9! because all the others end in zero, zero, zero! (Reason: for example, 36! 36x35x34x33x32x31.......x10x9x8.....3x2x1)  I honestly dont know the second it could be anything from 0 to 9. Im soory this awnser is probably not helpful. 

 

angelthecutehamster out! cool

 Jan 14, 2021

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