Вариант 1. Задание 2: Выполните действия: a) \frac{1}{3} + \frac{2}{5}, б) \frac{5}{5} - \frac{9}{20}, в) \frac{23}{43} - \frac{11}{70}, г) \frac{1}{8} + \frac{7}{12} - \frac{5}{9}

a) \frac{1}{3} + \frac{2}{5} = \frac{5}{15} + \frac{6}{15} = \frac{11}{15} б) \frac{5}{5} - \frac{9}{20} = 1 - \frac{9}{20} = \frac{20}{20} - \frac{9}{20} = \frac{11}{20} в) \frac{23}{43} - \frac{11}{70} = \frac{23 \cdot 70 - 11 \cdot 43}{43 \cdot 70} = \frac{1610 - 473}{3010} = \frac{1137}{3010} г) \frac{1}{8} + \frac{7}{12} - \frac{5}{9} = \frac{9}{72} + \frac{42}{72} - \frac{40}{72} = \frac{51}{72} - \frac{40}{72} = \frac{11}{72}