Решебник по математике 4 класс Петерсон рабочая тетрадь Часть 1, 2, 3 Часть 2 | Страница 20

\[\boxed{Страница\ 21.}\]

\[\boxed{\mathbf{3.}}\]

\[y < 240\]

\[y = 0 - наименьшее\ решение\ \]

\[неравенства.\]

\[Ответ:\ y = 0.\]

\[\boxed{\mathbf{4.}}\]

\[\textbf{а)}\ \left( \frac{12}{50} + x \right) - \frac{3}{50} = \frac{27}{50}\]

\[\frac{12}{50} + x = \frac{27}{50} + \frac{3}{50}\]

\[\frac{12}{50} + x = \frac{30}{50}\]

\[x = \frac{30}{50} - \frac{12}{50}\]

\[x = \frac{18}{50}.\]

\[\textbf{б)}\ \frac{31}{42} - \left( y + \frac{9}{42} \right) = \frac{15}{42}\]

\[y + \frac{9}{42} = \frac{31}{42} - \frac{15}{42}\]

\[y + \frac{9}{42} = \frac{16}{42}\]

\[y = \frac{16}{42} - \frac{9}{42}\]

\[y = \frac{7}{42}.\]

\[\boxed{\mathbf{5.}}\]

\[= 210 \cdot 4 + 105 = 840 + 105 =\]

\[= 945\]

\[\textbf{б)}\ 4 \cdot 5 \cdot 367 \cdot 2 \cdot 25 =\]

\[= 100 \cdot 10 \cdot 367 = 367\ 000\]

\[\textbf{в)}\ 974 \cdot 5 + 5 \cdot 26 =\]

\[= 5 \cdot (974 + 26) = 5 \cdot 1000 =\]

\[= 5000\]

\[\boxed{\mathbf{6.}}\]

\[\textbf{а)}\ 6\frac{3}{5} = 5\frac{8}{5}\]

\[\textbf{б)}\ 2\frac{16}{10} = 3\frac{6}{10}\]

\[\textbf{в)}\ 9 = 8\frac{6}{6}\]