23. 2 17/21 - 1 7/21.

Привет! Давай решим примеры из твоего учебника. Вот пошаговые решения для всех задач: ### Задания 23–35 23. $2\frac{17}{21} - 1\frac{7}{21} = (2-1) + \frac{17-7}{21} = 1\frac{10}{21}$ 24. $5\frac{3}{17} - 2\frac{5}{17} = 4\frac{20}{17} - 2\frac{5}{17} = 2\frac{15}{17}$ 25. $5\frac{2}{3} + 3\frac{1}{4} = 5\frac{8}{12} + 3\frac{3}{12} = 8\frac{11}{12}$ 26. $4\frac{1}{7} - 2\frac{3}{5} = 4\frac{5}{35} - 2\frac{21}{35} = 3\frac{40}{35} - 2\frac{21}{35} = 1\frac{19}{35}$ 27. $-2\frac{1}{5} - 1\frac{1}{3} = -2\frac{3}{15} - 1\frac{5}{15} = -3\frac{8}{15}$ 28. $2\frac{7}{15} - 4\frac{2}{3} = 2\frac{7}{15} - 4\frac{10}{15} = -(4\frac{10}{15} - 2\frac{7}{15}) = -2\frac{3}{15} = -2\frac{1}{5}$ 29. $132 \cdot 23 = 3036$ 30. $240 \cdot 50 = 12000$ 31. $15334 : 34 = 451$ 32. $37741 : 47 = 803$ 33. $\frac{1}{2} \cdot \frac{3}{7} = \frac{3}{14}$ 34. $\frac{5}{13} \cdot \frac{26}{35} = \frac{1}{1} \cdot \frac{2}{7} = \frac{2}{7}$ 35. $2\frac{3}{5} \cdot 1\frac{2}{3} = \frac{13}{5} \cdot \frac{5}{3} = \frac{13}{3} = 4\frac{1}{3}$ ### Задания 36–48 36. $14 \cdot \frac{7}{9} = \frac{98}{9} = 10\frac{8}{9}$ 37. $3\frac{7}{12} \cdot 4 = \frac{43}{12} \cdot 4 = \frac{43}{3} = 14\frac{1}{3}$ 38. $0 \cdot 2\frac{1}{8} = 0$ 39. $1 : \frac{2}{3} = 1 \cdot \frac{3}{2} = 1,5$ 40. $\frac{5}{7} : \frac{5}{14} = \frac{5}{7} \cdot \frac{14}{5} = \frac{14}{7} = 2$ 41. $\frac{7}{8} : 1 = \frac{7}{8}$ 42. $\frac{3}{5} : 1\frac{2}{3} = \frac{3}{5} : \frac{5}{3} = \frac{3}{5} \cdot \frac{3}{5} = \frac{9}{25} = 0,36$ 43. $10\frac{1}{7} : \frac{71}{7} = \frac{71}{7} : \frac{71}{7} = 1$ 44. $\frac{8}{9} : 2\frac{2}{3} = \frac{8}{9} : \frac{8}{3} = \frac{8}{9} \cdot \frac{3}{8} = \frac{3}{9} = \frac{1}{3}$ 45. $-1\frac{1}{5} : \frac{15}{6} = -\frac{6}{5} : \frac{5}{2} = -\frac{6}{5} \cdot \frac{2}{5} = -\frac{12}{25} = -0,48$ 46. $-2\frac{2}{3} \cdot \left(-\frac{5}{22}\right) = -\frac{8}{3} \cdot \left(-\frac{5}{22}\right) = \frac{4 \cdot 5}{3 \cdot 11} = \frac{20}{33}$ 47. $-\frac{13}{14} : 1\frac{11}{28} = -\frac{13}{14} : \frac{39}{28} = -\frac{13}{14} \cdot \frac{28}{39} = -\frac{1}{1} \cdot \frac{2}{3} = -\frac{2}{3}$ 48. $-1\frac{3}{7} : \left(-\frac{10}{21}\right) = -\frac{10}{7} : \left(-\frac{10}{21}\right) = \frac{10}{7} \cdot \frac{21}{10} = 3$ ### Задания 49–54 (Запись в виде десятичной дроби) 49. $3\frac{7}{10} = 3,7$ 50. $9\frac{3}{100} = 9,03$ 51. $\frac{233}{1000} = 0,233$ 52. $\frac{1}{100000} = 0,00001$ 53. $\frac{4}{5} = 0,8$ 54. $\frac{7}{8} = 0,875$