5. Найти разность дробей: a) 7/10 - 1/2 б) 13/20 - 3/8 в) 13/14 - 5/42 г) 3 1/6 - 2 1/12

Решение:

1. a) $$\frac{7}{10} - \frac{1}{2} = \frac{7}{10} - \frac{5}{10} = \frac{2}{10} = \frac{1}{5}$$
2. б) $$\frac{13}{20} - \frac{3}{8} = \frac{26}{40} - \frac{15}{40} = \frac{11}{40}$$
3. в) $$\frac{13}{14} - \frac{5}{42} = \frac{39}{42} - \frac{5}{42} = \frac{34}{42} = \frac{17}{21}$$
4. г) $$3 \frac{1}{6} - 2 \frac{1}{12} = 3 \frac{2}{12} - 2 \frac{1}{12} = 1 \frac{1}{12}$$