\[\boxed{\mathbf{739\ (739)}\mathbf{.}\mathbf{\ }Еуроки\ - \ ДЗ\ без\ мороки}\]
\[\textbf{а)}\ ( + 1) + ( + 3) = + 4\]
\[( - 4) + ( + 1) = - 3\]
\[( - 3) + ( - 3) = - 6\]
\[\textbf{б)}\ ( + 4) + ( - 3) = + 1\]
\[( - 5) + ( - 2) = - 7\]
\[( + 3) + ( + 3) = + 6\]
\[\textbf{в)}\ ( + 1) + ( - 5) = - 4\]
\[( - 4) + ( - 6) = - 10\]
\[( + 7) + ( - 3) = + 4\]