a)  $\underline{2\frac{3}{5}}+1\frac{1}{4}+\underline{3\frac{2}{5}}=6+1\frac{1}{4}=7\frac{1}{4}$  

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b)  $\underline{5\frac{1}{3}}+3\frac{1}{5}+\underline{1\frac{2}{3}}=7+3\frac{1}{5}=10\frac{1}{5}$  

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c)  $\underline{8\frac{7}{12}}+3\frac{13}{15}+\underline{3\frac{2}{12}}+\underline{2\frac{3}{12}}=14+3\frac{13}{15}=17\frac{13}{15}$  

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d)  $\underline{3\frac{2}{7}}+\underline{\underline{4\frac{5}{9}}}+\underline{2\frac{6}{7}}+\underline{\underline{1\frac{2}{9}}}+\underline{\underline{2\frac{2}{9}}}=6\frac{1}{7}+8=14\frac{1}{7}$