[tex][tex] \frac{30}{45}= \frac{6}{9}= \frac{2}{3} (simplifici) \\ \frac{98}{56} = \frac{49}{28} = \frac{7}{4} (simplifici) \\ \frac{21}{35}= \frac{3}{5} (simplifici) [/tex][/tex]
[tex]\frac{2}{3} + \frac{7}{4} + \frac{3}{5}= \frac{2*20}{3*20}+ \frac{7*15}{4*15}+ \frac{3*12}{5*12} = \frac{40}{60} + \frac{105}{60}+ \frac{36}{60} = \frac{40+105+36}{60} = \frac{115}{60}[/tex]
