Вычислите: а) 18 : 10 7/20; 4 1/2 : 2/3; 5 17/24 : 2/3; в) 63 1/3 : 5 2/11; 6 1/8 : 3 1/3; 5 9/11 : 13 5/7; б) 17 5/14 : 2 2/27; 39 : 9 3/5; 7/12 : 3 1/16; г) 32 : 9 3/5; 25 5/7 : 1 1/35; 21 7/9 : 4 2/3.

1. \(18:10\frac{7}{20}=18:\frac{207}{20}=18\cdot\frac{20}{207}=\frac{120}{69}=\frac{40}{23}=1\frac{17}{23}\).
2. \(4\frac12:\frac23=\frac92\cdot\frac32=\frac{27}{4}=6\frac34\).
3. \(5\frac{17}{24}:\frac23=\frac{137}{24}\cdot\frac32=\frac{137}{16}=8\frac{9}{16}\).
4. \(63\frac13:5\frac{2}{11}=\frac{190}{3}:\frac{57}{11}=\frac{190}{3}\cdot\frac{11}{57}=\frac{110}{9}=12\frac29\).
5. \(6\frac18:3\frac13=\frac{49}{8}:\frac{10}{3}=\frac{49}{8}\cdot\frac{3}{10}=\frac{147}{80}=1\frac{67}{80}\).
6. \(5\frac{9}{11}:13\frac57=\frac{64}{11}:\frac{96}{7}=\frac{64}{11}\cdot\frac{7}{96}=\frac{14}{33}\).
7. \(17\frac{5}{14}:2\frac{2}{27}=\frac{243}{14}:\frac{56}{27}=\frac{243}{14}\cdot\frac{27}{56}=\frac{6561}{784}=8\frac{289}{784}\).
8. \(39:9\frac35=39:\frac{48}{5}=39\cdot\frac5{48}=\frac{65}{16}=4\frac1{16}\).
9. \(\frac7{12}:3\frac1{16}=\frac7{12}:\frac{49}{16}=\frac7{12}\cdot\frac{16}{49}=\frac4{21}\).
10. \(32:9\frac35=32:\frac{48}{5}=32\cdot\frac5{48}=\frac{10}{3}=3\frac13\).
11. \(25\frac57:1\frac1{35}=\frac{180}{7}:\frac{36}{35}=\frac{180}{7}\cdot\frac{35}{36}=25\).
12. \(21\frac79:4\frac23=\frac{196}{9}:\frac{14}{3}=\frac{196}{9}\cdot\frac3{14}=\frac{14}{3}=4\frac23\).

Ответ: \(1\frac{17}{23};\ 6\frac34;\ 8\frac{9}{16};\ 12\frac29;\ 1\frac{67}{80};\ \frac{14}{33};\ 8\frac{289}{784};\ 4\frac1{16};\ \frac4{21};\ 3\frac13;\ 25;\ 4\frac23\).