\ANG{
Berechne geschickt:\qquad
(a)\quad$\D\frac{77}{21}\ \ \mbox{von}\ \ \frac{10}{11} $;\qquad
(b)\quad$\D\frac{169}{21}\cdot\frac{14}{13} $

}
\LSG{
(a)\quad$\D 3\frac13$,\quad (b)\quad$\D 8\frac23$
}

