1) b + 5 9/10 = 7 5/12; 2) a − 3 7/15 = 4 11/20; 3) x − 2 8/15 = 3 7/12; 4) y + 4 7/10 = 8 8/15.

1. \(b=7\frac{5}{12}-5\frac{9}{10}=\frac{445}{60}-\frac{354}{60}=\frac{91}{60}=1\frac{31}{60}\).
2. \(a=4\frac{11}{20}+3\frac{7}{15}=\frac{251}{60}+\frac{202}{60}=\frac{453}{60}=7\frac{11}{20}\).
3. \(x=3\frac{7}{12}+2\frac{8}{15}=\frac{43}{12}+\frac{38}{15}=\frac{215+152}{60}=6\frac{7}{60}\).
4. \(y=8\frac{8}{15}-4\frac{7}{10}=\frac{128}{15}-\frac{47}{10}=2\frac{5}{6}\).

Ответ: 1) \(b=1\frac{31}{60}\); 2) \(a=7\frac{11}{20}\); 3) \(x=6\frac{7}{60}\); 4) \(y=2\frac{5}{6}\).