Applicare la formula: $ab$$=ab$, dove $ab=3.4\cdot 0.2$, $a=\frac{17}{5}$ e $b=\frac{1}{5}$

Applicare la formula: $ab$$=ab$, dove $ab=1.2\cdot -0.8$, $a=\frac{6}{5}$ e $b=-\frac{4}{5}$

Applicare la formula: $a+b$$=a+b$, dove $a=\frac{17}{25}$, $b=-\frac{24}{25}$ e $a+b=0.68-0.96+\frac{3.2}{0.16}$

Applicare la formula: $\frac{a}{b}$$=\frac{a}{b}$, dove $a=\frac{16}{5}$, $b=\frac{4}{25}$ e $a/b=\frac{3.2}{0.16}$

Applicare la formula: $a+b$$=a+b$, dove $a=20$, $b=-\frac{7}{25}$ e $a+b=-0.28+20$