1.
[tex]72:5 = 14 \:rest\: 2[/tex]
2.
[tex]\frac{3}{2}\cdot \frac{4}{6} + \frac{1}{2}\div \frac{1}{2}=\frac{3\cdot 4}{2\cdot 6} + \frac{1}{2}\cdot \frac{2}{1} = \frac{12}{12} + \frac{1\cdot 2}{1\cdot 2} = 1 + \frac{2}{2} = 1 + 1 = 2[/tex]
3.
[tex]unghi\:dreptunghic = 90^{\circ}\Rightarrow unghi\:dreptunghic - 72^{\circ} = 90^{\circ} - 72^{\circ} = 18^{\circ}[/tex]
