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

Subtraction : Subtraction is the mathematical operation that describes decreasing a number by an amount equal to a second number. The mathematical symbol for subtraction is the minus sign $-.$ The term subtraction is also used for a generalization of this basic operation on numbers to functions, vectors and matrices.

Number : A number $x$ is a mathematical symbol representing a quantity.

Square : A square is a quadrilateral with four right angles and four equal length sides. A square is a special case of a rectangle and a special case of a rhombus.

Square root : The square root of $x$ denoted by $\sqrt{x}$ is the positive number such that $(\sqrt{x})^2=\sqrt{x}\cdot \sqrt{x}=x.$ For example $\sqrt{9}=3.$

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

Factor : If a natural number is divisible by a second natural number, that second natural number is called a factor of the first natural number. For example the factors of 12 are 1,2,3,4,6 and 12.

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

Line : A line AB is a one-dimensional shape that includes the points A and B, all the points on the line segment in between A and B and all the points of the straight extension of the line segment beyond A and B. A line does not have an endpoint.

Scale : Scale refers to the size of a shape. A scale drawing changes a shape to a similar shape of a different size.