ALGEBRA

Algebra - A branch of mathematics that substitutes letters for numbers. An algebraic equation represents a scale, what is done on one side of the scale with a number is also done to the other side of the scale. The numbers are the constants.
Algebra can include real numbers, complex numbers, matrices, vectors etc. Moving from Arithmetic to Algebra will look something like this: Arithmetic: 3 + 4 = 3 + 4 in Algebra it would look like: x + y = y + x

DOMAIN OF AN ALGEBRAIC EXPRESSION

   The set of real numbers for which an algebraic expressions is defined is the domain of the expression.

INTEGERS - are whole numbers that describe opposite.

                           - are the counting numbers, their negatives and zero.

NATURAL NUMBERS - also known as counting numbers, are the numbers beginning from 1.

WHOLE NUMBERS - are the numbers beginning from 0. It combines the set of natural numbers
                                       and the number zero.

RATIONAL NUMBERS - are numbers that can be presented as the quotient of two integers p and
                                           q, where q is not equal to zero. This includes integers,terminating decimals
                                           and repeating decimals as well as fractions.
IRRATIONAL NUMBERS - are any real number that cannot be written in fraction form. These 
                                                numbers include the non-terminating, non-repeating decimals.
REAL NUMBERS - are combination of rational and irrational numbers.