The given equation is:
\[
18B12P4M8Q6
\]
Substitute the symbols based on the provided clues:
- \( B \) denotes \( \times \), so \( 18B12 = 18 \times 12 = 216 \).
- \( P \) denotes \( \div \), so \( 216P4 = 216 \div 4 = 54 \).
- \( M \) denotes \( - \), so \( 54M8 = 54 - 8 = 46 \).
- \( Q \) denotes \( + \), so \( 46Q6 = 46 + 6 = 52 \).
Thus, the result is \( 52 \).