④) 1) 7/8 · 1/7 = ? 2) 27 · 4/9 = ? 3) 2⅕ · 0 = ? 4) 12⅓ · 3⅗ = ?

Решение:

1. 1) \( \frac{7}{8} \cdot \frac{1}{7} = \frac{1}{8} \cdot \frac{1}{1} = \frac{1}{8} \)
2. 2) \( 27 \cdot \frac{4}{9} = \frac{27}{1} \cdot \frac{4}{9} = 3 \cdot 4 = 12 \)
3. 3) \( 2\frac{1}{5} \cdot 0 = 0 \)
4. 4) \( 12\frac{1}{3} \cdot 3\frac{3}{5} = \frac{37}{3} \cdot \frac{18}{5} = \frac{37}{1} \cdot \frac{6}{5} = \frac{222}{5} = 44\frac{2}{5} \)

Ответ: 1) \(\frac{1}{8}\); 2) 12; 3) 0; 4) \(44\frac{2}{5}\).