Решение:
- 1) a) \( \frac{1}{5} + \frac{4}{15} = \frac{3}{15} + \frac{4}{15} = \frac{7}{15} \)
- 6) \( \frac{2}{3} - \frac{5}{12} = \frac{8}{12} - \frac{5}{12} = \frac{3}{12} = \frac{1}{4} \)
- в) \( 5 \frac{1}{7} + 7 \frac{13}{21} = 5 \frac{3}{21} + 7 \frac{13}{21} = 12 \frac{16}{21} \)
- 2) a) \( \frac{3}{8} - \frac{1}{9} = \frac{27}{72} - \frac{8}{72} = \frac{19}{72} \)
- 6) \( \frac{5}{6} + \frac{3}{11} = \frac{55}{66} + \frac{18}{66} = \frac{73}{66} = 1 \frac{7}{66} \)
- в) \( 9 \frac{1}{29} - 1 \frac{3}{4} = 9 \frac{4}{116} - 1 \frac{87}{116} = 8 \frac{120}{116} - 1 \frac{87}{116} = 7 \frac{33}{116} \)
- 3) a) \( \frac{7}{30} - \frac{31}{45} = \frac{21}{90} - \frac{62}{90} = -\frac{41}{90} \)
- 6) \( 2 \frac{1}{20} - 6 \frac{9}{40} = 2 \frac{2}{40} - 6 \frac{9}{40} = 1 \frac{42}{40} - 6 \frac{9}{40} = -4 \frac{27}{40} \)
- в) \( \frac{5}{18} - 2 \frac{23}{30} = \frac{25}{90} - 2 \frac{69}{90} = 1 \frac{115}{90} - 2 \frac{69}{90} = -1 \frac{54}{90} = -1 \frac{3}{5} \)
Ответ: 1) a) 7/15; 6) 1/4; в) 12 16/21; 2) a) 19/72; 6) 1 7/66; в) 7 33/116; 3) a) -41/90; 6) -4 27/40; в) -1 3/5