Resposta:
a)3/8 + 9/10
[tex]\frac{15+36}{40} \\\\\frac{51}{40}[/tex]
b)9/9 + 4/3
[tex]\frac{9+12}{9}\\\\\frac{21}{9} :(3)\\\\=\frac{7}{3}[/tex]
c)5/12 + 6/16
[tex]\frac{20+18}{48}\\\\\frac{38}{48} :(2)\\\\\frac{19}{24}[/tex]
d)7/20 + 8/18
[tex]\frac{63+80}{180}\\\\\frac{143}{180}[/tex]
