$\begin{array}{l}A = \{x\in \Bbb R\,|\, x \leq 6\}\\ \longrightarrow A = (-\infty;6]\\ B = \{x \in \Bbb R\,|\,0\leq x <8\}\\ \longrightarrow B = [0;8)\\ +) \quad A \cap B = [0;6]\\ +) \quad A \cup B = (-\infty;8)\\ +) \quad A\backslash B = (-\infty;0)\\ +) \quad B \backslash A =(6;8)\\ +) \quad C_{\Bbb R}(A) = \Bbb R \backslash A = (6;+\infty)\\ +) \quad C_{\Bbb R}(B) = \Bbb R \backslash B = (-\infty;0)\cup [8;+\infty) \end{array}$