What is the unit’s digit of this expression?
Number Theory
Level
2
What is the unit’s digit of the following?
The answer is 3.
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1 solution
5! through 2018! all end in a 0, so all we need to consider is 1! + 2! + 3! + 4! which is 1 + 2 + 6 + 24 = 33. So the units digits is 3.