Brilli the ant is considering the complexities of a 5-dimensional universe. She wants to count the number of integer points that are distance away from the origin. Let be the set of ordered 5-tuples of integers such that However, being an ant, she doesn't have enough toes to record numbers that are above 10. Let be the units digit of
Determine
Details and assumptions
Note: You are not asked to find the last digit of the sum, but the sum of all the last digits.
For a set , denotes the number of elements in . You can read up on set notation.