№3. Выполните действия: а) (12rac{7}{20} + 7rac{3}{20} - 4rac{}{20}) б) (71rac{8}{13} + 8rac{12}{13} + 9rac{}{13}) в) (11rac{21}{28} - 9rac{12}{28} + rac{1}{28}) г) (24 - 8rac{7}{11} - rac{4}{11}) д) ((10 - 6rac{15}{28}) + (2rac{15}{28} - rac{17}{28})) е) (5rac{16}{24} - (2rac{15}{24} - 1rac{17}{24}) + 17rac{5}{24})

а) (12rac{7}{20} + 7rac{3}{20} - 4rac{}{20} = (12+7-4) + (rac{7}{20} + rac{3}{20} - rac{0}{20}) = 15 + rac{10}{20} = 15 + rac{1}{2} = 15rac{1}{2}) б) (71rac{8}{13} + 8rac{12}{13} + 9rac{}{13} = (71+8+9) + (rac{8}{13} + rac{12}{13} + rac{0}{13}) = 88 + rac{20}{13} = 88 + 1rac{7}{13} = 89rac{7}{13}) в) (11rac{21}{28} - 9rac{12}{28} + rac{1}{28} = (11-9) + (rac{21}{28} - rac{12}{28} + rac{1}{28}) = 2 + rac{10}{28} = 2 + rac{5}{14} = 2rac{5}{14}) г) (24 - 8rac{7}{11} - rac{4}{11} = (24-8) - (rac{7}{11} + rac{4}{11}) = 16 - rac{11}{11} = 16 - 1 = 15) д) ((10 - 6rac{15}{28}) + (2rac{15}{28} - rac{17}{28}) = (10 - 6rac{15}{28}) + (2rac{15}{28} - rac{17}{28}) = 3rac{13}{28} + 1rac{26}{28} = 4 + rac{13+26}{28} = 4 + rac{39}{28} = 4 + 1rac{11}{28} = 5rac{11}{28}) е) (5rac{16}{24} - (2rac{15}{24} - 1rac{17}{24}) + 17rac{5}{24} = 5rac{16}{24} - (rac{63}{24} - rac{41}{24}) + 17rac{5}{24} = 5rac{16}{24} - rac{22}{24} + 17rac{5}{24} = 5rac{16}{24} - rac{22}{24} + 17rac{5}{24} = 4rac{38}{24} + 17rac{5}{24} = 21 + rac{43}{24} = 21 + 1rac{19}{24} = 22rac{19}{24})