2024 AMC 8

Solution 1

We can rewrite the expression as . We note that the units digit of is because all the units digits of the five numbers are and , which has a units digit of . Now, we have something with a units digit of subtracted from , and so the units digit of this expression is .

Solution 2

We only care about the units digits. Thus, ends in , after regrouping(10-2) ends in , ends in , ends in , and ends in .