\[ 7 \frac{37}{42} = \frac{7 \cdot 42 + 37}{42} = \frac{294 + 37}{42} = \frac{331}{42} \]
\[ 1 \frac{11}{14} = \frac{1 \cdot 14 + 11}{14} = \frac{25}{14} \]
\[ 2 \frac{11}{15} = \frac{2 \cdot 15 + 11}{15} = \frac{30 + 11}{15} = \frac{41}{15} \]
\[ \frac{25}{14} \cdot \frac{41}{15} = \frac{25 \cdot 41}{14 \cdot 15} = \frac{(5 \cdot 5) \cdot 41}{14 \cdot (3 \cdot 5)} = \frac{5 \cdot 41}{14 \cdot 3} = \frac{205}{42} \]
\[ \frac{331}{42} - \frac{205}{42} = \frac{331 - 205}{42} = \frac{126}{42} \]
\[ \frac{126}{42} = 3 \]
Ответ: 3.