18 3/8 + 4 5/6

1. Convert the mixed numbers to improper fractions:
18 \frac{3}{8} = \frac{147}{8}
4 \frac{5}{6} = \frac{29}{6}

2. Find a common denominator for the fractions:
The least common denominator of 8 and 6 is 24.

3. Convert the fractions to have the common denominator:
\frac{147}{8} = \frac{147 \times 3}{8 \times 3} = \frac{441}{24}
\frac{29}{6} = \frac{29 \times 4}{6 \times 4} = \frac{116}{24}

4. Add the fractions:
\frac{441}{24} + \frac{116}{24} = \frac{557}{24}

5. Simplify the result and convert back to a mixed number:
\frac{557}{24} = 23 \frac{5}{24}

Final answer is 23 \frac{5}{24}