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

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

Equilateral : A polygon that has side lengths that are all equal is called equilateral polygon.

Hexagon : A hexagon is a polygon with six corners. The sum of the angles in a hexagon is $720^{\circ}.$

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

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.

Sum : A sum is the result of an addition.

Addition : Addition is the mathematical operation that describes increasing a number by an amount equal to a second number. The mathematical symbol for addition is the plus sign $+.$ The term addition is also used for a generalization of this basic operation on numbers to functions, vectors and matrices.

Comparing coefficients : Comparing coefficients means to check if all the coefficients of two polynomials coincide. For example to check if a polynomial equals zero you can equivalently check if all of its coefficients are zero.

Division : Division is the mathematical operation that divides objects equally into groups. More generally $x\div y$ is defined as the number that if multiplied by $y$ equals $x.$

Equation : An equation is a mathematical statement in which two expressions are written with an equal sign in between. A solution of an equation is a set of variables that makes the statement a true statement.

Solution : A solution to an equation is a choice of variables that when substituted into the equation results in a true statement.