\[\boxed{\text{904.\ }\text{еуроки}\text{-}\text{ответы}\text{\ }\text{на}\text{\ }\text{пятёрку}}\]
\[\textbf{а)}\ N \cap Z = N,\ \ N \cup Z = Z\]
\[\textbf{б)}\ Z \cap Q = Z,\ \ Z \cup Q = Q\]
\[\textbf{в)}\ Q \cap I = \varnothing,\ \ Q \cup I = R\]