$3\frac{7}{16}+2\frac{5}{32}=3+\frac{7}{16}+2+\frac{5}{32}=(3+2)+({\frac{7}{16}}^{/2}+\frac{5}{32})=5+(\frac{14}{32}+\frac{5}{32})=5+\frac{19}{32}=5\frac{19}{32}$

$1\frac{1}{12}+3\frac{4}{9}=1+\frac{1}{12}+3+\frac{4}{9}=(1+3)+({\frac{1}{12}}^{/3}+{\frac{4}{9}}^{/4})=4+(\frac{3}{36}+\frac{16}{36})=4+\frac{19}{36}=4\frac{19}{36}$

$4\frac{1}{6}+5\frac{3}{14}+6\frac{2}{21}=4+\frac{1}{6}+5+\frac{3}{14}+6+\frac{2}{21}=(4+5+6)+({\frac{1}{6}}^{/7}+{\frac{3}{14}}^{/3}+{\frac{2}{21}}^{/2})=15+(\frac{7}{42}+\frac{9}{42}+\frac{4}{42})=15+\frac{20}{42}=15+\frac{10}{21}=15\frac{10}{21}$