\[ 5\frac{1}{3} - \frac{5}{6} = \frac{16}{3} - \frac{5}{6} = \frac{32}{6} - \frac{5}{6} = \frac{27}{6} = \frac{9}{2} = 4\frac{1}{2} \] см
\[ 5\frac{1}{3} \cdot 2\frac{1}{4} = \frac{16}{3} \cdot \frac{9}{4} = \frac{4 \cdot 3}{1 \cdot 1} = 12 \] см
\[ V = a \cdot b \cdot c = 4\frac{1}{2} \cdot 5\frac{1}{3} \cdot 12 = \frac{9}{2} \cdot \frac{16}{3} \cdot 12 = \frac{3 \cdot 8 \cdot 12}{1 \cdot 1 \cdot 1} = 288 \] см3
Ответ: 288 см3
\[ 5\frac{1}{4} \cdot 3 = \frac{21}{4} \cdot 3 = \frac{63}{4} = 15\frac{3}{4} \] дм
\[ 15\frac{3}{4} - 5\frac{1}{4} = 10\frac{2}{4} = 10\frac{1}{2} = 10.5 \] дм
Ответ: 10,5 дм
\[ 1 + \frac{1}{4} = \frac{5}{4}, \quad 1 + \frac{1}{5} = \frac{6}{5}, \quad 1 + \frac{1}{6} = \frac{7}{6}, \quad \dots, \quad 1 + \frac{1}{99} = \frac{100}{99} \]
\[ \frac{5}{4} \cdot \frac{6}{5} \cdot \frac{7}{6} \cdot \dots \cdot \frac{100}{99} = \frac{\cancel{5}}{\cancel{4}} \cdot \frac{\cancel{6}}{\cancel{5}} \cdot \frac{\cancel{7}}{\cancel{6}} \cdot \dots \cdot \frac{100}{\cancel{99}} = \frac{100}{4} = 25 \]
Ответ: 25
\[ 1.6 \cdot \frac{5}{8} = \frac{16}{10} \cdot \frac{5}{8} = \frac{8 \cdot 2 \cdot 5}{5 \cdot 2 \cdot 8} = 1 \]
Ответ: а) увеличится, б) не изменится