Задание 1. Найдите значение выражения: 1) (\frac{17}{10} - \frac{1}{20}) \cdot \frac{2}{15} 2) (\frac{5}{22} - \frac{8}{11}) \cdot \frac{11}{5} 3) (\frac{5}{26} - \frac{3}{25}) \cdot \frac{13}{2} 4) (\frac{10}{13} + \frac{15}{4}) \cdot \frac{26}{5} 5) (\frac{17}{26} + \frac{11}{13}) \cdot \frac{17}{6} 6) (\frac{11}{12} + \frac{11}{20}) \cdot \frac{15}{8} 7) (\frac{3}{4} - \frac{1}{6}) \cdot 3 8) (\frac{2}{5} + \frac{13}{15}) \cdot 6 9) (\frac{3}{8} - \frac{1}{20}) \cdot 10 10) (\frac{2}{20} + \frac{7}{30}) \cdot 15 11) (\frac{9}{10} - \frac{7}{15}) \cdot 3 12) (\frac{1}{6} + \frac{1}{4}) \cdot 9

Решение: 1) (\frac{17}{10} - \frac{1}{20}) \cdot \frac{2}{15} = (\frac{34}{20} - \frac{1}{20}) \cdot \frac{2}{15} = \frac{33}{20} \cdot \frac{2}{15} = \frac{33 \cdot 2}{20 \cdot 15} = \frac{66}{300} = \frac{11}{50} 2) (\frac{5}{22} - \frac{8}{11}) \cdot \frac{11}{5} = (\frac{5}{22} - \frac{16}{22}) \cdot \frac{11}{5} = \frac{-11}{22} \cdot \frac{11}{5} = -\frac{1}{2} \cdot \frac{11}{5} = -\frac{11}{10} 3) (\frac{5}{26} - \frac{3}{25}) \cdot \frac{13}{2} = (\frac{5 \cdot 25 - 3 \cdot 26}{26 \cdot 25}) \cdot \frac{13}{2} = (\frac{125 - 78}{650}) \cdot \frac{13}{2} = \frac{47}{650} \cdot \frac{13}{2} = \frac{47}{50 \cdot 13} \cdot \frac{13}{2} = \frac{47}{100} 4) (\frac{10}{13} + \frac{15}{4}) \cdot \frac{26}{5} = (\frac{40 + 195}{52}) \cdot \frac{26}{5} = \frac{235}{52} \cdot \frac{26}{5} = \frac{235}{2} \cdot \frac{1}{5} = \frac{47}{2} = 23.5 5) (\frac{17}{26} + \frac{11}{13}) \cdot \frac{17}{6} = (\frac{17 + 22}{26}) \cdot \frac{17}{6} = \frac{39}{26} \cdot \frac{17}{6} = \frac{3}{2} \cdot \frac{17}{6} = \frac{17}{4} = 4.25 6) (\frac{11}{12} + \frac{11}{20}) \cdot \frac{15}{8} = (\frac{55 + 33}{60}) \cdot \frac{15}{8} = \frac{88}{60} \cdot \frac{15}{8} = \frac{22}{15} \cdot \frac{15}{8} = \frac{22}{8} = \frac{11}{4} = 2.75 7) (\frac{3}{4} - \frac{1}{6}) \cdot 3 = (\frac{9 - 2}{12}) \cdot 3 = \frac{7}{12} \cdot 3 = \frac{7}{4} = 1.75 8) (\frac{2}{5} + \frac{13}{15}) \cdot 6 = (\frac{6 + 13}{15}) \cdot 6 = \frac{19}{15} \cdot 6 = \frac{19 \cdot 2}{5} = \frac{38}{5} = 7.6 9) (\frac{3}{8} - \frac{1}{20}) \cdot 10 = (\frac{15 - 2}{40}) \cdot 10 = \frac{13}{40} \cdot 10 = \frac{13}{4} = 3.25 10) (\frac{2}{20} + \frac{7}{30}) \cdot 15 = (\frac{6 + 14}{60}) \cdot 15 = \frac{20}{60} \cdot 15 = \frac{1}{3} \cdot 15 = 5 11) (\frac{9}{10} - \frac{7}{15}) \cdot 3 = (\frac{27 - 14}{30}) \cdot 3 = \frac{13}{30} \cdot 3 = \frac{13}{10} = 1.3 12) (\frac{1}{6} + \frac{1}{4}) \cdot 9 = (\frac{2 + 3}{12}) \cdot 9 = \frac{5}{12} \cdot 9 = \frac{5 \cdot 3}{4} = \frac{15}{4} = 3.75