Real number:  Any number which can be negative, positive, or zero.

Additive inverses: The opposite of a number.

Identity element for addition:  Zero (0).

Identity element for multiplication: One (1).

Integers: All numbers in the set containing positive integers, negative integers, and zero.

Irrational numbers: Any number that is impossible to write it as a fraction. A decimal number that doesn’t end or keeps repeating.

Negative integers: The numbers -1,-2,-3,-4, and so on.

Negative number: The opposite of a positive number.

Negative side: The side situated at the left of the origin in a horizontal number line.

Positive integers:  Natural numbers: 1, 2, 3, 4, 5, ...

Positive number: The opposite of a negative number.

Positive side:  The side situated to the right of the origin in a horizontal number line.

Real number:  Any number which can be negative, positive, or zero.

Reciprocals:  Any two numbers which multiplied give 1; also known as multiplicative inverse.

Whole numbers:  All numbers in the set containing zero and all positive integers.