2013 CEMC Gauss (Grade 8) Problems/Problem 2

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Problem

The value of $15 - 3 - 15$ is

$\textbf{(A)}\ -18 \qquad\textbf{(B)}\ -15 \qquad\textbf{(C)}\ 3 \qquad\textbf{(D)}\ -3 \qquad\textbf{(E)}\ -33$

Solution 1

$15 - 3 - 15 = 12 - 15 = \boxed {\textbf {(D) } -3}$

~anabel.disher

Solution 2

Let $x = 15$. We then have:

$x - 3 - x = x - x - 3 = \boxed {\textbf {(D) } -3}$

~anabel.disher