\[\boxed{\mathbf{4.}\mathbf{145}}\]
\[\textbf{а)}\ 5 + 0 = 5\]
\[\textbf{б)}\ 0 + ( - 7) = - 7\]
\[\textbf{в)} - 9,3 + 0 = - 9,3\]
\[\textbf{г)} - 14 + 14 = 0\]
\[\textbf{д)}\ 10,5 + ( - 10,5) = 0\]
\[\textbf{е)}\ 0 + ( - 7,4) = - 7,4\]
\[\textbf{ж)}\ 3\frac{1}{4} + \left( - 3\frac{1}{4} \right) = 0\]
\[\textbf{з)}\ 17\frac{1}{3} + 0 = 17\frac{1}{3}\]