B) 2 1/3 + (1/5 - 3/10) * 1/4

Решение:

• \[ 2 \frac{1}{3} + \left( \frac{1}{5} - \frac{3}{10} \right) \cdot \frac{1}{4} \]
• \[ \frac{7}{3} + \left( \frac{2 - 3}{10} \right) \cdot \frac{1}{4} \]
• \[ \frac{7}{3} + \left( -\frac{1}{10} \right) \cdot \frac{1}{4} \]
• \[ \frac{7}{3} - \frac{1}{40} \]
• \[ \frac{7 \cdot 40 - 1 \cdot 3}{3 \cdot 40} = \frac{280 - 3}{120} = \frac{277}{120} \]

Ответ: 277/120