\[\boxed{\mathbf{4.}\mathbf{150}}\]
\[\textbf{а)} - 6 + 4 - 9 = - 2 - 9 = - 11\]
\[\textbf{б)}\ 8 - 12 + 4 = - 4 + 4 = 0\]
\[\textbf{в)} - 1 - 5 + 9 = - 6 + 9 = 3\]
\[\textbf{г)} - 2 - 3 + 5 = - 5 + 5 = 0\]
\[\textbf{д)} - 3 + 7 - 8 = 4 - 8 = - 4\]
\[\textbf{е)}\ 1 - 6 + 10 = - 5 + 10 = 5\]