\[- 15 < - 2\ \ \ \ \ \ \ \ \ | - 3\]
\[- 15 - 3 < - 2 - 3\]
\[- 18 < - 5\]
\[- 15 < - 2\ \ \ \ \ | - ( - 5)\]
\[- 15 - ( - 5) < - 2 - ( - 5)\]
\[- 15 + 5 < - 2 + 5\]
\[- 10 < 3.\]