Учебник по математике 6 класс Виленкин

авторы: Н.Я. Виленкин, В.И. Жохов, А.С. Чесноков, С.И. Шварцбурд.

издательство: Мнемозина 2012 год

Номер №380

х + 2 \frac{2}{11} = 5

х = 5 - 2 \frac{2}{11} = 4 \frac{11}{11} - 2 \frac{2}{11} = 2 \frac{9}{11}

26 \frac{5}{8} + a = 30

a = 30 - 26 \frac{5}{8} = 29 \frac{8}{8} - 26 \frac{5}{8} = 3 \frac{3}{8}

n - 6 \frac{5}{6} = \frac{2}{9}

n = \frac{2}{9} + 6 \frac{5}{6} = \frac{4}{18} + 6 \frac{15}{18} = 6 \frac{19}{18} = 7 \frac{1}{18}

11 \frac{1}{4} - х = 3 \frac{7}{10}

- х = 3 \frac{7}{10} - 11 \frac{1}{4}

х = 11 \frac{1}{4} - 3 \frac{7}{10} = 11 \frac{5}{20} - 3 \frac{14}{20} = 10 \frac{25}{20} - 3 \frac{14}{20} = 7 \frac{11}{20}

3 \frac{11}{24} - х = 1 \frac{1}{6} + 1 \frac{1}{9}

- х = 1 \frac{1}{6} + 1 \frac{1}{9} - 3 \frac{11}{24}

х = 3 \frac{11}{24} - 1 \frac{1}{6} - 1 \frac{1}{9} = 3 \frac{33}{72} - 1 \frac{12}{72} - 1 \frac{8}{72} = 1 \frac{13}{72}

y + \frac{5}{7} - \frac{1}{8} = \frac{2}{3} - \frac{1}{14}

y = \frac{2}{3} - \frac{1}{14} - \frac{5}{7} + \frac{1}{8} = \frac{112}{168} - \frac{12}{168} - \frac{120}{168} + \frac{21}{168} = \frac{1}{168}