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.

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

Denominator : The denominator of a fraction $\frac{a}{b}$ is the number $b$ below the fraction bar.

Fraction : A fraction is a number that can be written as $\frac{a}{b}$ with an integer $a$ and a natural numbers $b.$ A fraction $\frac{a}{b}$ is the result of the division $a\div b.$ Examples of fractions are $\frac{1}{2}, -\frac{2}{3}$ and $\frac{3}{2}.$

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

Numerator : The numerator of a fraction $\frac{a}{b}$ is the number $a$ above the fraction bar.

Function : A function is a mapping in which every element in one set is mapped to exactly one element of a second set. Most often the mapping is described using a rule. For example the function $f(x)=x+1$ maps 2 to 3 and -1 to 0.

Graph : The graph of a function is the set of points $\{(x,f(x))\}$ that can be blotted in a coordinate system.

Intersect : Two shapes intersect if they have at least one point in common.

Line of symmetry : A line of symmetry is a line such that reflecting a two-dimensional shape on that line leaves the shape unchanged.

Point : A point is an element in a space. Shapes are made of sets of points.

Squared : $x$ squared refers to the number $x^2=x\cdot x.$ For example 3 squared equals 9.

X-axis : The horizontal axis in a two-dimensional coordinate system.

X-coordinate : The first coordinate in a two-dimensional coordinate system.

Y-axis : The vertical axis in a two-dimensional coordinate system.

Y-coordinate : The second coordinate in a two-dimensional coordinate system.