\[\boxed{\mathbf{876\ (876)}\mathbf{.}\mathbf{\ }Еуроки\ - \ ДЗ\ без\ мороки}\]
\[\textbf{а)}\ N \cap Z = N\]
\[N \cap Q = N\]
\[Z \cap Q = Z\]
\[\textbf{б)}\ N \cup Z = Z\]
\[N \cup Q = Q\]
\[Z \cup Q = Q\]