1. **Problem 1:** Calculate how many people were still at the sports day in the evening. Step 1: Start with the number of people in the morning: $1248$. Step 2: Add the people who joined in the afternoon: $1248 + 896 = 2144$. Step 3: Subtract the people who left by evening: $2144 - 1037 = 1107$. So, there were $1107$ people still at the sports day in the evening. --- 2. **Problem 2:** Two classrooms have a total of $78$ students. One classroom has $16$ more students than the other. Find the number of students in each class. Step 1: Let the number of students in the smaller class be $x$. Step 2: Then the other class has $x + 16$ students. Step 3: The total number of students is the sum of both classes: $$x + (x + 16) = 78$$ Step 4: Simplify and solve for $x$: $$2x + 16 = 78$$ $$2x = 78 - 16$$ $$2x = 62$$ $$x = \frac{62}{2} = 31$$ Step 5: Number of students in the smaller class is $31$, and in the larger class is $31 + 16 = 47$. Answer: Smaller class has $31$ students, and larger class has $47$ students.