(1)

$\left(8,9+16,5\right):2,54=25,4:2,54=10$

(2)

$\left(2\frac{1}{2}-13\frac{1}{4}\right)\cdot \left(-\frac{9}{10}\right)=-\left(13\frac{1}{4}-2\frac{2}{4}\right)\cdot \left(-\frac{9}{10}\right)=\cdot 12\frac{5}{4}-2\frac{2}{4})\cdot \frac{9}{10}=$