1. **Problem 1: Calculate the total number of students.** There are 31 students in each class and 22 classes. 2. **Formula:** Total students = number of students per class $\times$ number of classes. 3. **Calculation:** $$31 \times 22 = 682$$ 4. **Explanation:** Multiply the number of students in one class by the total number of classes to find the total students. 5. **Problem 2: Calculate the volume of a cube with side length 6 units.** 6. **Formula:** Volume of a cube = side length $^3$. 7. **Calculation:** $$6^3 = 6 \times 6 \times 6 = 216$$ 8. **Explanation:** Cube the side length to find the volume. **Final answers:** - Total students = 682 - Volume of cube = 216 cubic units