A number theory problem by Trishit Chandra
Number Theory
Level
3
What is the digit at the unit place of the following : (1!-2!+3!-4!+5!-.....+25!)^(1!-2!+3!-4!+5!-.....+25!)
The answer is 1.
This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try
refreshing the page, (b) enabling javascript if it is disabled on your browser and,
finally, (c)
loading the
non-javascript version of this page
. We're sorry about the hassle.
we know that after 5!(including)every number will have the unit digit as 0.We just need to consider 1!-2!+3!-4! which is equal to -19.=>the unit digit of the whole expression will be 1.1^anything has unit digit 1.