1.4 Сложение обыкновенных дробей

Question

Вопрос:

Ответ:

Accepted Answer

$$\frac{1}{5} + \frac{1}{3} = \frac{3}{15} + \frac{5}{15} = \frac{8}{15}$$
$$\frac{1}{4} - \frac{5}{12} = \frac{3}{12} - \frac{5}{12} = -\frac{2}{12} = -\frac{1}{6}$$
$$\frac{1}{10} + \frac{1}{6} = \frac{3}{30} + \frac{5}{30} = \frac{8}{30} = \frac{4}{15}$$
$$\frac{6}{17} - 9 = \frac{6}{17} - \frac{9 \cdot 17}{17} = \frac{6}{17} - \frac{153}{17} = -\frac{147}{17}$$
$$6\frac{7}{20} - 8 = -2 + \frac{7}{20} = -\frac{40}{20} + \frac{7}{20} = -\frac{33}{20}$$
$$-7\frac{17}{29} - \frac{12}{29} = -7 - \frac{17}{29} - \frac{12}{29} = -7 - \frac{29}{29} = -7 - 1 = -8$$
$$\frac{4}{7} + \frac{9}{14} = \frac{8}{14} + \frac{9}{14} = \frac{17}{14} = 1\frac{3}{14}$$
$$\frac{3}{4} - \frac{5}{12} = \frac{9}{12} - \frac{5}{12} = \frac{4}{12} = \frac{1}{3}$$