a) $$20\frac{3}{4} - 17$$
$$20\frac{3}{4} - 17 = 20 - 17 + \frac{3}{4} = 3 + \frac{3}{4} = 3\frac{3}{4}$$
Ответ: $$3\frac{3}{4}$$
б) $$13\frac{8}{11} - 5\frac{2}{11}$$
$$13\frac{8}{11} - 5\frac{2}{11} = (13 - 5) + (\frac{8}{11} - \frac{2}{11}) = 8 + \frac{6}{11} = 8\frac{6}{11}$$
Ответ: $$8\frac{6}{11}$$
в) $$34\frac{7}{15} - 34$$
$$34\frac{7}{15} - 34 = 34 - 34 + \frac{7}{15} = \frac{7}{15}$$
Ответ: $$\frac{7}{15}$$
г) $$29\frac{19}{23} - 7\frac{6}{23}$$
$$29\frac{19}{23} - 7\frac{6}{23} = (29 - 7) + (\frac{19}{23} - \frac{6}{23}) = 22 + \frac{13}{23} = 22\frac{13}{23}$$
Ответ: $$22\frac{13}{23}$$