Applicare la formula: $a+b$$=a+b$, dove $a=23$, $b=-\frac{979}{5}$ e $a+b=\frac{9}{5}-195.8+23$

Applicare la formula: $\frac{a}{b}+c$$=\frac{a+cb}{b}$, dove $a/b+c=\frac{9}{5}-172.8$, $a=9$, $b=5$, $c=-\frac{864}{5}$ e $a/b=\frac{9}{5}$

Applicare la formula: $ab$$=ab$, dove $ab=-172.8\cdot 5$, $a=-\frac{864}{5}$ e $b=5$

Applicare la formula: $a+b$$=a+b$, dove $a=9$, $b=-864$ e $a+b=9-864$

Applicare la formula: $\frac{a}{b}$$=\frac{a}{b}$, dove $a=-855$, $b=5$ e $a/b=-\frac{855}{5}$