Решение задания 518

1. a) $$\frac{1}{3} + \frac{1}{5} = \frac{5}{15} + \frac{3}{15} = \frac{8}{15}$$

2. б) $$\frac{1}{3} - \frac{1}{4} = \frac{4}{12} - \frac{3}{12} = \frac{1}{12}$$

3. в) $$2\frac{1}{9} + 1\frac{1}{3} = 2\frac{1}{9} + 1\frac{3}{9} = 3\frac{4}{9}$$

4. г) $$2\frac{1}{2} - 1\frac{1}{3} = \frac{5}{2} - \frac{4}{3} = \frac{15}{6} - \frac{8}{6} = \frac{7}{6} = 1\frac{1}{6}$$

5. д) $$3 - 1\frac{2}{5} = \frac{15}{5} - \frac{7}{5} = \frac{8}{5} = 1\frac{3}{5}$$

6. е) $$\frac{2}{3} \cdot \frac{3}{4} = \frac{2 \cdot 3}{3 \cdot 4} = \frac{6}{12} = \frac{1}{2}$$

7. ж) $$\frac{4}{5} \cdot 5 = \frac{4 \cdot 5}{5} = \frac{20}{5} = 4$$

8. з) $$\frac{5}{9} \cdot \frac{1}{5} = \frac{5 \cdot 1}{9 \cdot 5} = \frac{5}{45} = \frac{1}{9}$$

9. и) $$1\frac{1}{3} \cdot \frac{3}{4} = \frac{4}{3} \cdot \frac{3}{4} = \frac{4 \cdot 3}{3 \cdot 4} = \frac{12}{12} = 1$$

10. к) $$2\frac{1}{4} \cdot 1\frac{1}{3} = \frac{9}{4} \cdot \frac{4}{3} = \frac{9 \cdot 4}{4 \cdot 3} = \frac{36}{12} = 3$$