Ответ:
\(23\frac{11}{13}+7\frac{2}{13}=30\frac{13}{13}=31\).
\(4\frac{1}{4}+15=19\frac{1}{4}\).
\(2\frac{2}{3}+5\frac{2}{3}=7\frac{4}{3}=8\frac{1}{3}\).
Ответ: \(31;\ 19\frac{1}{4};\ 8\frac{1}{3}\).
\(23\frac{11}{13}+7\frac{2}{13}=30\frac{13}{13}=31\).
\(4\frac{1}{4}+15=19\frac{1}{4}\).
\(2\frac{2}{3}+5\frac{2}{3}=7\frac{4}{3}=8\frac{1}{3}\).
Ответ: \(31;\ 19\frac{1}{4};\ 8\frac{1}{3}\).