13. Выполните действия: a) $$1\frac{5}{7} + 2\frac{4}{7} =$$ б) $$5\frac{3}{8} - 1\frac{5}{8} =$$ в) $$1\frac{2}{3} \cdot 2\frac{1}{5} =$$ г) $$2\frac{16}{27} : 1\frac{5}{9} =$$ д) $$\frac{17}{24} - (\frac{1}{4} + \frac{5}{24}) =$$ e) $$8,24 + 3,456 =$$ ж) $$0,235 \cdot 1,06 =$$ з) $$32,2 : 0,04 =$$</p>

a) $$1\frac{5}{7} + 2\frac{4}{7} = (1+2) + (\frac{5}{7} + \frac{4}{7}) = 3 + \frac{9}{7} = 3 + 1\frac{2}{7} = 4\frac{2}{7}$$

б) $$5\frac{3}{8} - 1\frac{5}{8} = 4\frac{11}{8} - 1\frac{5}{8} = (4-1) + (\frac{11}{8} - \frac{5}{8}) = 3 + \frac{6}{8} = 3\frac{3}{4}$$

в) $$1\frac{2}{3} \cdot 2\frac{1}{5} = \frac{5}{3} \cdot \frac{11}{5} = \frac{5 \cdot 11}{3 \cdot 5} = \frac{11}{3} = 3\frac{2}{3}$$

г) $$2\frac{16}{27} : 1\frac{5}{9} = \frac{70}{27} : \frac{14}{9} = \frac{70}{27} \cdot \frac{9}{14} = \frac{70 \cdot 9}{27 \cdot 14} = \frac{5 \cdot 1}{3 \cdot 1} = \frac{5}{3} = 1\frac{2}{3}$$

д) $$\frac{17}{24} - (\frac{1}{4} + \frac{5}{24}) = \frac{17}{24} - (\frac{6}{24} + \frac{5}{24}) = \frac{17}{24} - \frac{11}{24} = \frac{6}{24} = \frac{1}{4}$$

е) $$8,24 + 3,456 = 11,696$$

ж) $$0,235 \cdot 1,06 = 0,2491$$

з) $$32,2 : 0,04 = 805$$

Ответы:

a) $$4\frac{2}{7}$$

б) $$3\frac{3}{4}$$

в) $$3\frac{2}{3}$$

г) $$1\frac{2}{3}$$

д) $$\frac{1}{4}$$

е) $$11,696$$

ж) $$0,2491$$

з) $$805$$