Write an expression for the area of the shaded region and explain how the diagram shows your expression.

A big square that is 4×5. First column has 4 shaded boxes out of 5.

To find the area of the shaded region in the diagram, we can break down the square into smaller sections.

The total area of the square is given by its length multiplied by its width. In this case, the length is 4 units and the width is 5 units, so the total area of the square is 4 × 5 = 20 square units.

Now let's consider the shaded region. We are told that the first column of the square has 4 shaded boxes out of 5. This means that out of the 5 boxes in the first column, 4 of them are shaded.

Since each column is the same width, we can calculate the area of one column by dividing the total area of the square by the number of columns. In this case, the total area is 20 square units and there are 5 columns, so each column has an area of 20 ÷ 5 = 4 square units.

Since the first column has 4 shaded boxes, the area of the shaded region in the first column is 4 square units.

So, the expression for the area of the shaded region is 4 square units. This is because the shaded region is composed of just the first column, which has an area of 4 square units.

20 boxes, 4 shaded, so 4/20