6 5 6-5-= 13 13

6 6/13 - 5 11/13 = 1 6/13 - 11/13 = 18/13 - 11/13 = 7/13

$$6 \frac{6}{13} - 5 \frac{11}{13} = (6 - 5) + (\frac{6}{13} - \frac{11}{13}) = 1 + \frac{6-11}{13} = 1 - \frac{5}{13} = \frac{13}{13} - \frac{5}{13} = \frac{13-5}{13} = \frac{8}{13}$$

Или

$$6 \frac{6}{13} - 5 \frac{11}{13} = \frac{6 \cdot 13 + 6}{13} - \frac{5 \cdot 13 + 11}{13} = \frac{78+6}{13} - \frac{65+11}{13} = \frac{84}{13} - \frac{76}{13} = \frac{84-76}{13} = \frac{8}{13}$$

Ответ: $$\frac{8}{13}$$