Remember these important rules:
\[
\boxed{
\begin{aligned}
\text{Circular DNA:}&\quad \\
\text{Fragments}=\text{Restriction Sites}[0.2cm] \\
\text{Linear DNA:}&\quad \\
\text{Fragments}=\text{Restriction Sites}+1
\end{aligned}
}
\]
This shortcut is frequently tested in biotechnology and molecular biology examinations.