18. Expressed as the simplest mixed number, \( 33 / 8 \) is equal to ?

To convert the improper fraction \( \frac{33}{8} \) into a mixed number, divide 33 by 8. The whole number part is 4 (since \( 8 \times 4 = 32 \)) and the remainder is 1. Hence, \( \frac{33}{8} \) as a mixed number is \( 4 \frac{1}{8} \). Additionally, it's important to ensure that the fraction part is in its simplest form. In this case, \( \frac{1}{8} \) cannot be simplified further, so our final answer remains \( 4 \frac{1}{8} \).