Задание 1. Вычислите: 1) 7/12 + 13/15; 2) 5/8 + 3/5; 3) 3/4 − 5/15; 4) 3/15 − 3/12; 5) 4/10 · 10/32; 6) 4/15 · 27/40; 7) 23/25 : 23/21; 8) 19/24 : 25/33; 9) 15 1/4 + 6/10; 10) 1 13/25 + 3 9/10; 11) 20 3/4 − 12 4/5; 12) 1 1/15 − 1 4/24; 13) 3 1/5 · 8 1/4; 14) 1 9/11 · 2 2/10; 15) 1 3/15 : 1 18/22; 16) 18 2/5 : 6 4/7; 17) 4,08 + 0,225; 18) 0,7 + 9,625; 19) 28,75 − 1,228; 20) 0,386 − 0,6; 21) 2,25 · 12,5; 22) 21,375 · 1,08; 23) 0,945 : 0,25; 24) 16,5 : 3,3.

1. Приводим к общему знаменателю: \(\frac{7}{12}+\frac{13}{15}=\frac{35}{60}+\frac{52}{60}=\frac{87}{60}=\frac{29}{20}=1\frac{9}{20}\).
2. \(\frac{5}{8}+\frac{3}{5}=\frac{25}{40}+\frac{24}{40}=\frac{49}{40}=1\frac{9}{40}\).
3. \(\frac{3}{4}-\frac{5}{15}=\frac{3}{4}-\frac{1}{3}=\frac{5}{12}\).
4. \(\frac{3}{15}-\frac{3}{12}=\frac{1}{5}-\frac{1}{4}=-\frac{1}{20}\).
5. \(\frac{4}{10}\cdot\frac{10}{32}=\frac{2}{5}\cdot\frac{5}{16}=\frac{1}{8}\).
6. \(\frac{4}{15}\cdot\frac{27}{40}=\frac{9}{50}\).
7. \(\frac{23}{25}:\frac{23}{21}=\frac{23}{25}\cdot\frac{21}{23}=\frac{21}{25}\).
8. \(\frac{19}{24}:\frac{25}{33}=\frac{19}{24}\cdot\frac{33}{25}=\frac{209}{200}=1\frac{9}{200}\).
9. \(15\frac{1}{4}+\frac{6}{10}=\frac{61}{4}+\frac{3}{5}=\frac{317}{20}=15\frac{17}{20}\).
10. \(1\frac{13}{25}+3\frac{9}{10}=\frac{38}{25}+\frac{39}{10}=\frac{271}{50}=5\frac{21}{50}\).
11. \(20\frac{3}{4}-12\frac{4}{5}=\frac{83}{4}-\frac{64}{5}=\frac{159}{20}=7\frac{19}{20}\).
12. \(1\frac{1}{15}-1\frac{4}{24}=\frac{16}{15}-\frac{7}{6}=-\frac{1}{10}\).
13. \(3\frac{1}{5}\cdot8\frac{1}{4}=\frac{16}{5}\cdot\frac{33}{4}=\frac{132}{5}=26\frac{2}{5}\).
14. \(1\frac{9}{11}\cdot2\frac{2}{10}=\frac{20}{11}\cdot\frac{11}{5}=4\).
15. \(1\frac{3}{15}:1\frac{18}{22}=\frac{6}{5}:\frac{20}{11}=\frac{6}{5}\cdot\frac{11}{20}=\frac{33}{50}\).
16. \(18\frac{2}{5}:6\frac{4}{7}=\frac{92}{5}:\frac{46}{7}=\frac{92}{5}\cdot\frac{7}{46}=\frac{14}{5}=2\frac{4}{5}\).
17. \(4,08+0,225=4,305\).
18. \(0,7+9,625=10,325\).
19. \(28,75-1,228=27,522\).
20. \(0,386-0,6=-0,214\).
21. \(2,25\cdot12,5=28,125\).
22. \(21,375\cdot1,08=23,085\).
23. \(0,945:0,25=3,78\).
24. \(16,5:3,3=5\).

Ответ: 1) 1 9/20; 2) 1 9/40; 3) 5/12; 4) −1/20; 5) 1/8; 6) 9/50; 7) 21/25; 8) 1 9/200; 9) 15 17/20; 10) 5 21/50; 11) 7 19/20; 12) −1/10; 13) 26 2/5; 14) 4; 15) 33/50; 16) 2 4/5; 17) 4,305; 18) 10,325; 19) 27,522; 20) −0,214; 21) 28,125; 22) 23,085; 23) 3,78; 24) 5.