4. \( \begin{array}{l}7 \frac{8}{12} \\ -2 \frac{3}{12} \\ \text { 8. } 5 \frac{2}{8}-3 \frac{7}{8}\end{array} \)

To tackle these arithmetic problems involving mixed numbers, it helps to convert them into improper fractions. For instance, \( 7 \frac{8}{12} \) becomes \( \frac{88}{12} \) and \( 2 \frac{3}{12} \) becomes \( \frac{27}{12} \). Subtracting \( 2 \frac{3}{12} \) from \( 7 \frac{8}{12} \) gives you \( \frac{61}{12} \) or \( 5 \frac{1}{12} \). For the second problem, convert \( 5 \frac{2}{8} \) to \( \frac{42}{8} \) and \( 3 \frac{7}{8} \) to \( \frac{31}{8} \). Subtracting these gives you \( \frac{11}{8} \), which can be simplified to \( 1 \frac{3}{8} \).