The problem in the image asks for expressions to calculate the perimeter ("omkreds") and area ("areal") of a square with side length $a$. Here are the expressions:

1. Perimeter: The perimeter of a square is the sum of all four sides. Since each side is of length $a$, the perimeter is: $\text{Perimeter} = 4 \times a = 4 * a$

2. Area: The area of a square is the length of one side squared. Since each side is of length $a$, the area is: $\text{Area} = a^2 = a * a$

Would you like more details or have any further questions?

Here are 5 related questions to expand the topic:

1. How does the formula for the perimeter change for a rectangle?
2. What happens to the area if the side length $a$ doubles?
3. Can you derive the formulas for perimeter and area for any polygon?
4. How does the area of a square relate to the area of a circle inscribed in it?
5. What real-world situations might require calculating the perimeter or area of a square?

Tip: Always remember that the area is in square units (like $\text{cm}^2$) while the perimeter is in linear units (like cm).