Выполните сложение или вычитание: 1) 15/8 − 7/8; 2) 12/15 + 7/15; 3) 45/100 + 35/100; 4) 65/76 − 25/76; 5) 43/56 − 33/56; 6) 6/23 + 20/23; 7) 4/7 + 2/7; 8) 3/4 + 3/4; 9) 7 − 4/9; 10) 8 7/6 − 6; 11) 4 + 1 3/5; 12) 7 − 2 1/2.

1. \(\frac{15}{8}-\frac{7}{8}=\frac{8}{8}=1\).
2. \(\frac{12}{15}+\frac{7}{15}=\frac{19}{15}=1\frac{4}{15}\).
3. \(\frac{45}{100}+\frac{35}{100}=\frac{80}{100}=\frac{4}{5}\).
4. \(\frac{65}{76}-\frac{25}{76}=\frac{40}{76}=\frac{10}{19}\).
5. \(\frac{43}{56}-\frac{33}{56}=\frac{10}{56}=\frac{5}{28}\).
6. \(\frac{6}{23}+\frac{20}{23}=\frac{26}{23}=1\frac{3}{23}\).
7. \(\frac{4}{7}+\frac{2}{7}=\frac{6}{7}\).
8. \(\frac{3}{4}+\frac{3}{4}=\frac{6}{4}=1\frac{1}{2}\).
9. \(7-\frac{4}{9}=\frac{63}{9}-\frac{4}{9}=\frac{59}{9}=6\frac{5}{9}\).
10. \(8\frac{7}{6}-6=9\frac{1}{6}-6=3\frac{1}{6}\).
11. \(4+1\frac{3}{5}=5\frac{3}{5}\).
12. \(7-2\frac{1}{2}=4\frac{1}{2}\).

Ответ: 1; 1\(\frac{4}{15}\); \(\frac{4}{5}\); \(\frac{10}{19}\); \(\frac{5}{28}\); 1\(\frac{3}{23}\); \(\frac{6}{7}\); 1\(\frac{1}{2}\); 6\(\frac{5}{9}\); 3\(\frac{1}{6}\); 5\(\frac{3}{5}\); 4\(\frac{1}{2}\).