|
Stitchawl, I'm afraid you're thinking much too difficult. You only need to look at the first factorials.
- Finding the factorials:
1! = 1
2! = 2*1 = 2
3! = 3*2 = 6
4! = 4*6 = 24
5! = 5*24 = 120 (=12*10)
6! = 6*12*10 = 720 (=72*10)
7! = 7*72*10 = 5040
...
Since getting the next factorial always involves a multiplication with 10 all following factorials will end with 0.
- Adding the factorials:
1
+ 2
+ 6
+ 24
+ 120
+ 720
+ 5040
+ ???0
+ ???0
---------
?????3
(Sorry, I'm not able to put the numbers in proper columns so that all last digits are shown one below the other). As all the following factorials end with a 0 the last digit 3 from 1+2+6+4 = 3 can't change anymore and you can ignore them all.
|