(9/16 + 2 3/8) * 4

Решение:

1. \[ 2\frac{3}{8} = \frac{2 \times 8 + 3}{8} = \frac{19}{8} \]
2. \[ \frac{9}{16} + \frac{19}{8} = \frac{9}{16} + \frac{19 \times 2}{8 \times 2} = \frac{9}{16} + \frac{38}{16} = \frac{47}{16} \]
3. \[ \frac{47}{16} \times 4 = \frac{47}{16} \times \frac{4}{1} = \frac{47 \times 4}{16} = \frac{188}{16} = \frac{47}{4} = 11,75 \]

Ответ: 11,75