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

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

Absolute value : The absolute value $|x|$ of a number $x$ is defined as the value of $x$ ignoring any potential minus sign. For example $|-2|=2$ and $|2|=2.$ In other words $|x|=x$ for $x\geq 0$ and $|x|=-x$ for $x\lt 0.$

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.

Negative : A number is negative if it is $\lt 0.$

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

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.

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 $\frac{3}{2}.$

Integer : An integer is any ot the numbers $\ldots, -3, -2, -1, 0, 1, 2, 3, \ldots.$

Negative : A number is negative if it is $\lt 0.$

Positive : Positive means $\geq 0.$