1) Вычислите: a) \(\frac{3}{10}-\frac{9}{25}:(4-1\frac{9}{10})+\frac{4}{7}\) б) 1,54-0,5-1,3.

а) Вычислите: \(\frac{3}{10}-\frac{9}{25}:(4-1\frac{9}{10})+\frac{4}{7}\)

1. \(4-1\frac{9}{10} = 4 - \frac{19}{10} = \frac{40}{10} - \frac{19}{10} = \frac{21}{10}\)
2. \(\frac{9}{25} : \frac{21}{10} = \frac{9}{25} \cdot \frac{10}{21} = \frac{9 \cdot 10}{25 \cdot 21} = \frac{3 \cdot 2}{5 \cdot 7} = \frac{6}{35}\)
3. \(\frac{3}{10} - \frac{6}{35} = \frac{3}{10}^{(7} - \frac{6}{35}^{(2} = \frac{21 - 12}{70} = \frac{9}{70}\)
4. \(\frac{9}{70} + \frac{4}{7} = \frac{9}{70} + \frac{4}{7}^{(10} = \frac{9 + 40}{70} = \frac{49}{70} = \frac{7}{10}\)

Ответ: \(\frac{7}{10}\)

б) Вычислите: 1,54 - 0,5 - 1,3

1. 1,54 - 0,5 = 1,04
2. 1,04 - 1,3 = -0,26

Ответ: -0,26