\[\boxed{\text{4.}\text{\ }еуроки - ответы\ на\ пятёрку}\]
Пояснение.
N – множество натуральных чисел (1, 2, 3 и так далее – числа, которые называют при счете).
Решение.
\[36 = \frac{36}{1};\]
\[- 45 = \frac{- 45}{1};\]
\[4,2 = \frac{21}{5};\]
\[- 0,8 = \frac{- 4}{5};\]
\[15\frac{1}{6} = \frac{91}{6};\]
\[- \frac{2}{9} = \frac{- 2}{9}.\]
\[\boxed{\text{4\ (4).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
Пояснение.
Решение.
\[\textbf{а)}\ \frac{5^{\backslash 4}}{6} + \frac{1^{\backslash 6}}{4} = \frac{5 \cdot 4 + 6 \cdot 1}{24} =\]
\[= \frac{20 + 6}{24} = \frac{26}{24} = \frac{13}{12} = 1\frac{1}{12}\]
\[\textbf{б)}\ \frac{7^{\backslash 3}}{8} - \frac{5^{\backslash 4}}{6} = \frac{7 \cdot 3 - 5 \cdot 4}{24} =\]
\[= \frac{21 - 20}{24} = \frac{1}{24}\]
\[\textbf{в)}\ \frac{3^{\backslash 3}}{10} - \frac{4^{\backslash 2}}{15} = \frac{3 \cdot 3 - 4 \cdot 2}{30} =\]
\[= \frac{9 - 8}{30} = \frac{1}{30}\]
\[\textbf{г)}\ 5 - 3\frac{2}{7} = 4\frac{7}{7} - 3\frac{2}{7} =\]
\[= (4 - 3) + \left( \frac{7}{7} - \frac{2}{7} \right) = 1 + \frac{5}{7} =\]
\[= 1\frac{5}{7}\]
\[\textbf{д)}\ \frac{4}{9} \cdot \frac{3}{8} = \frac{4 \cdot 3}{9 \cdot 8} = \frac{1 \cdot 1}{3 \cdot 2} = \frac{1}{6}\ \]
\[\textbf{е)}\ \frac{5}{8}\ :\frac{9}{10} = \frac{5}{8} \cdot \frac{10}{9} = \frac{5 \cdot 10}{8 \cdot 9} =\]
\[= \frac{5 \cdot 5}{4 \cdot 9} = \frac{25}{36}\]
\[\textbf{ж)}\ 2\frac{6}{7}\ :1\frac{3}{7} = \frac{20}{7}\ :\frac{10}{7} = \frac{20}{7} \cdot \frac{7}{10} =\]
\[= \frac{20 \cdot 7}{7 \cdot 10} = 2\]
\[\textbf{з)}\ 6\frac{3}{5} \cdot 10 = \frac{33}{5} \cdot 10 = \frac{33 \cdot 10}{5} =\]
\[= 33 \cdot 2 = 66\]