A rectangle made of unit squares is shown below.

What is the area, in square units, of the rectangle?

Part of the model shown below has been covered with unit squares without any gaps or overlaps.

What will be the area, in square units, of the model after it is completely covered with unit squares?

The side lengths of a playground are shown below.

What is the area, in square meters, of the playground?

A third-grade class is having a car wash. They put the same amount of water in each bucket, as shown.

Which expression can be used to find the total amount of water, in gallons, in all the buckets?