Математика: 5 класс. Тренажер «Умножение и деление обыкновенных дробей».

Ответы к тренажеру на деление и умножение обыкновенных дробей: 1. $\frac{1}{2} \cdot \frac{2}{3} = \frac{1 \cdot 2}{2 \cdot 3} = \frac{1}{3}$ 2. $\frac{3}{4} \cdot \frac{3}{5} = \frac{3 \cdot 3}{4 \cdot 5} = \frac{9}{20}$ 3. $\frac{2}{3} \cdot \frac{1}{2} = \frac{2 \cdot 1}{3 \cdot 2} = \frac{1}{3}$ 4. $\frac{3}{4} : \frac{2}{5} = \frac{3}{4} \cdot \frac{5}{2} = \frac{15}{8} = 1\frac{7}{8}$ 5. $\frac{1}{2} : \frac{5}{6} = \frac{1}{2} \cdot \frac{6}{5} = \frac{3}{5}$ 6. $\frac{3}{7} : \frac{11}{14} = \frac{3}{7} \cdot \frac{14}{11} = \frac{3 \cdot 2}{11} = \frac{6}{11}$ 7. $\frac{2}{5} : \frac{3}{7} = \frac{2}{5} \cdot \frac{7}{3} = \frac{14}{15}$ 8. $\frac{3}{4} : \frac{1}{8} = \frac{3}{4} \cdot 8 = 6$ 9. $\frac{4}{7} : \frac{2}{9} = \frac{4}{7} \cdot \frac{9}{2} = \frac{2 \cdot 9}{7} = \frac{18}{7} = 2\frac{4}{7}$ 10. $\frac{5}{8} : \frac{3}{4} = \frac{5}{8} \cdot \frac{4}{3} = \frac{5}{2 \cdot 3} = \frac{5}{6}$ 11. $\frac{2}{5} : \frac{3}{7} = \frac{2}{5} \cdot \frac{7}{3} = \frac{14}{15}$ 12. $\frac{4}{7} : \frac{2}{9} = \frac{4}{7} \cdot \frac{9}{2} = \frac{18}{7} = 2\frac{4}{7}$ 13. $\frac{5}{8} : \frac{3}{4} = \frac{5}{8} \cdot \frac{4}{3} = \frac{5}{6}$ 14. $1\frac{2}{3} : \frac{2}{5} = \frac{5}{3} \cdot \frac{5}{2} = \frac{25}{6} = 4\frac{1}{6}$ 15. $\frac{2}{5} : \frac{4}{7} = \frac{2}{5} \cdot \frac{7}{4} = \frac{7}{10} = 0,7$ 16. $\frac{11}{41} : \frac{22}{43} = \frac{11}{41} \cdot \frac{43}{22} = \frac{43}{41 \cdot 2} = \frac{43}{82}$ 17. $\frac{10}{19} : \frac{5}{38} = \frac{10}{19} \cdot \frac{38}{5} = 2 \cdot 2 = 4$ 18. $\frac{9}{13} : \frac{15}{26} = \frac{9}{13} \cdot \frac{26}{15} = \frac{3 \cdot 2}{5} = \frac{6}{5} = 1,2$ 19. $\frac{15}{28} : \frac{5}{21} = \frac{15}{28} \cdot \frac{21}{5} = \frac{3 \cdot 3}{4} = \frac{9}{4} = 2,25$ 20. $\frac{3}{5} : \frac{16}{15} = \frac{3}{5} \cdot \frac{15}{16} = \frac{3 \cdot 3}{16} = \frac{9}{16}$ 21. $\frac{8}{9} : \frac{8}{27} = \frac{8}{9} \cdot \frac{27}{8} = 3$ 22. $\frac{4}{5} : \frac{6}{13} = \frac{4}{5} \cdot \frac{13}{6} = \frac{2 \cdot 13}{5 \cdot 3} = \frac{26}{15} = 1\frac{11}{15}$ 23. $\frac{5}{21} : \frac{3}{7} = \frac{5}{21} \cdot \frac{7}{3} = \frac{5}{3 \cdot 3} = \frac{5}{9}$ 24. $\frac{17}{50} : \frac{51}{150} = \frac{17}{50} \cdot \frac{150}{51} = \frac{1 \cdot 3}{3} = 1$ 25. $\frac{2}{7} : \frac{56}{20} = \frac{2}{7} \cdot \frac{20}{56} = \frac{20}{7 \cdot 28} = \frac{5}{7 \cdot 7} = \frac{5}{49}$