a) $$6+8\frac{7}{13} = 14\frac{7}{13}$$
б) $$12 + 19\frac{5}{24} = 31\frac{5}{24}$$
г) $$13\frac{5}{101}+7\frac{25}{101} = (13+7)+(\frac{5}{101}+\frac{25}{101}) = 20 + \frac{30}{101} = 20\frac{30}{101}$$
д) $$4\frac{3}{7}+15\frac{4}{7} = (4+15)+(\frac{3}{7}+\frac{4}{7}) = 19 + \frac{7}{7} = 19 + 1 = 20$$
e) $$3\frac{9}{13}+4\frac{8}{13} = (3+4)+(\frac{9}{13}+\frac{8}{13}) = 7 + \frac{17}{13} = 7 + 1\frac{4}{13} = 8\frac{4}{13}$$
Ответ: a) $$14\frac{7}{13}$$; б) $$31\frac{5}{24}$$; г) $$20\frac{30}{101}$$; д) 20; e) $$8\frac{4}{13}$$