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

Even number : A number is called even if it is divisible by 2. A number is even if and only if it ends in 0, 2, 6 or 8.

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

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.

Multiple : A multiple of a number $x$ is any of the numbers $1x,2x,3x,4x,\ldots.$ For example the multiples of 7 include 7, 14, 21 and 70.

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

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

Positive : Positive means $\geq 0.$