$\text{a)}2,75+5\frac{1}{2}=2,75+5\frac{5}{10}=2,75+5,5=8,25$

$3\frac{2}{5}+6,5=3\frac{4}{10}+6,5=3,4+6,5=9,9$

$2\frac{1}{8}+1,125=2\frac{125}{1000}+1,125=2,125+1,125=3,25$

$0,2+3\frac{1}{6}=\frac{2}{10}+3\frac{1}{6}=\frac{6}{30}+3\frac{5}{30}=3\frac{11}{30}$

 

 

$\text{b)}1\frac{1}{3}+0,25=1\frac{1}{3}+\frac{1}{4}=1\frac{4}{12}+\frac{3}{12}=1\frac{7}{12}$

$2,73+9\frac{2}{3}=2\frac{73}{100}+9\frac{2}{3}=2\frac{219}{300}+9\frac{200}{300}=11\frac{419}{300}=12\frac{119}{300}$

$\frac{7}{100}+10,3=0,07+10,3=10,37$

$4\frac{5}{9}+1,5=4\frac{5}{9}+1\frac{1}{2}=4\frac{10}{18}+1\frac{9}{18}=5\frac{19}{18}=6\frac{1}{18}$