2024 AMC 8 Problems/Problem 1

Revision as of 14:13, 25 January 2024 by Dreamer1297 (talk | contribs) (Solution 2)

Problem

What is the ones digit of \[222,222-22,222-2,222-222-22-2?\] $\textbf{(A) } 0\qquad\textbf{(B) } 2\qquad\textbf{(C) } 4\qquad\textbf{(D) } 6\qquad\textbf{(E) } 8$

Solution 1

\[222,222-22,222-2,222-222-22-2\] \[\equiv 2-2-2-2-2-2\] \[\equiv -8\] \[\equiv 2\] So the solution is $(B)$ $2$

~nikhil ~ CXP

Solution 2

We can rewrite the expression as \[222,222-(22,222+2,222+222+22+2)\].

We note that the units digit of the addition is $0$ because all the units digits of the five numbers are $2$ and $5*2=10$, which has a units digit of $0$.

Now, we have something with a units digit of $0$ subtracted from $222,222$. The units digit of this expression is obviously $2$, and we get $\boxed{B}$ as our answer.

~ Dreamer1297