Count : To count means to find out the number of objects by adding one for every object.

Count down by 7 starting at 15.

The correct answer is 8. $15-7=8.$

Centimeter : A centimeter ($cm$) is $\frac{1}{100}$ of a meter.

Length : Length is the attribute of a one-dimensional shape that can be measured with a measuring tape.

Opposite side : In a quadrilateral the opposite side of a side refers to the side that does not share a corner with the original side.

Perimeter : The perimeter of a two-dimensional shape is the length of the boundary of the shape. For a polygon this is the same as the sum of all the side lengths. For example a triangle with side lengths 1, 2 and 3cm has a perimeter of 1+2+3=6cm. The perimeter of a circle is referred to as its circumference.

Rectangle : A rectangle is a quadrilateral with 4 right angles. Two opposing sides in a rectangle have the same length. They are sometimes referred to as the width and the length of the rectangle. To calculate the area of an rectangle one can multiply the width of the rectangle by the length of the rectangle. A square is the special case of a rectangle in which all side lengths are the same. Every rectangle is a parallelogram.

Sum : A sum is the result of an addition.

The perimeter is the sum of all the side lengths.

The correct answer is 18. In a rectangle two opposite sides have the same length, so the perimeter equals $4+4+5+5=2\cdot(4+5)=18.$

Area : The amount of unit squares that is needed to cover a 2-dimensional shape.

Centimeter : A centimeter ($cm$) is $\frac{1}{100}$ of a meter.

Height : In a triangle a height (or altitude) is the shortest line segment that connects a side to its opposing corner. A height of a triangle is perpendicular to the side is started at. The three heights of a triangle intersect in a point, the so called orthocenter of the triangle. In a parallelogram the height is the shortest distance between two opposing sides. In a pyramid the height is the shortest distance between the base area and the corner of the pyramid that is not part of the base area. In a prism the height is the shortest distance between the two base faces.

Length : Length is the attribute of a one-dimensional shape that can be measured with a measuring tape.

Rectangular prism : A rectangular prism is a prism that has rectangular bases.

Square centimeter : Square centimeter or $cm^2$ is a unit of measurement for measuring area. 1 square centimeter is the area of a square with side length 1 $cm,$ so 10,000 $cm^2$ are one $m^2.$

Sum : A sum is the result of an addition.

Surface area : The surface area of a three-dimensional shape is the area of the surface of the three-dimensional shape. For example the surface area of a cube with edge length 1 $cm$ is 6 $cm^2.$

The surface area is the area of all the sides combined.

The correct answer is 28. The right rectangular prism has 6 sides. Two of the sides have a width of 1 and a length of 2 and therefore an area in square cm of 2 each. Two of the sides have a width of 1 and a length of 4 and therefore an area in square cm of 4 each. The remaining two sides have a width of 2 and a length of 4 and therefore an area in square cm of 8 each. The sum of all the 6 side areas in square cm therefore is: $2\cdot2+2\cdot4+2\cdot8=28.$