№3. Найдите значение выражений: a) \(\frac{3}{10} + \frac{2}{15}\) б) \(\frac{2}{9} + \frac{1}{6}\) г) \(\frac{7}{9} - \frac{1}{4}\)

Ответ:

• а) \(\frac{3}{10} + \frac{2}{15} = \frac{3 \times 3}{10 \times 3} + \frac{2 \times 2}{15 \times 2} = \frac{9}{30} + \frac{4}{30} = \frac{13}{30}\)
• б) \(\frac{2}{9} + \frac{1}{6} = \frac{2 \times 2}{9 \times 2} + \frac{1 \times 3}{6 \times 3} = \frac{4}{18} + \frac{3}{18} = \frac{7}{18}\)
• г) \(\frac{7}{9} - \frac{1}{4} = \frac{7 \times 4}{9 \times 4} - \frac{1 \times 9}{4 \times 9} = \frac{28}{36} - \frac{9}{36} = \frac{19}{36}\)

Ответ: а) \(\frac{13}{30}\), б) \(\frac{7}{18}\), г) \(\frac{19}{36}\)