In a classroom, the students have to sit in four rows. Find the rule for the number of students in the class if the number of students in each row is n.

Answer

To find the rule for the number of students in a classroom where students are seated in four rows and each row has 'n' students, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the number of rows**: We know that there are 4 rows in the classroom.

2. **Identify the number of students in each row**: The problem states that the number of students in each row is 'n'.

3. **Calculate the total number of students**: To find the total number of students in the classroom, we need to multiply the number of rows by the number of students in each row. This can be expressed mathematically as:
\[ \text{Total number of students} = \text{Number of rows} \times \text{Number of students in each row} \]

4. **Substitute the known values**: We substitute the known values into the equation:
\[ \text{Total number of students} = 4 \times n \]

5. **Write the final expression**: Thus, the rule for the number of students in the class can be expressed as:
\[ \text{Total number of students} = 4n \]

### Final Answer:
The rule for the number of students in the class is \( 4n \).