Important Vocabulary to Know

Natural Numbers (counting numbers)

Whole Numbers

Integers- The natural numbers, their opposites and 0 form the set of integers:

Rational Numbers are numbers that can be expressed as fractions with denominators not equal to 0, i.e.

• This set includes all integers since any integer can be written as a fraction, i.e. is a rational number since it could be written as
• This set includes terminating decimals, i.e. 0.23 is a rational number since it could be written as .
• This set includes decimal numbers that repeat in a fixed block of digits, i.e. 0 .333… is a rational number since .

Irrational numbers are numbers that cannot be expressed as fractions with denominators not equal to 0.These numbers include non-repeating, non-terminating decimals i.e.

Real Numbers-

Ordering of the Real Numbers- For any two real numbers and b, a is less than b if a is to the left of b on a

0 a b

number line.

Opposite of a Real Number- each real number, except 0, can be paired with another real number that is the same distance from 0 on the number line, but in opposite directions. i.e. are opposite numbers

Double Negative Rule: for all values of x. Except for 0, the opposite of a number is found by changing the sign of the number.

Absolute value is the distance between 0 and the number on the number line. The absolute value of a number can never be negative. i.e.

Variables: letters used to represent numbers.

Algebraic Expression: is a way of representing a calculation with numbers, using letters to stand for some of the numbers i.e. 0.2B, ,

Evaluating Algebraic Expressions: We evaluate algebraic expressions by giving particular values to the variables in the expression.