Find the missing number: $\frac{3}{4}$ of $\square - \frac{2}{5}$ of $150 = 12 \times 3 + 9$.

Explanation

1. 01

   Right side: $12 \times 3 + 9 = 36 + 9 = 45$.

2. 02

   $\frac{2}{5}$ of $150 = 60$, so $\frac{3}{4}$ of $\square = 45 + 60 = 105$.

3. 03

   $\square = 105 \div \frac{3}{4} = 105 \times \frac{4}{3} = 140$.